
Class _JBo_4!i. 



Book. 






r 4 



GopightN . 



COPYRIGHT DEPOSIT 



HUME: 



THE RELATION OF 

THE TREATISE OF HUMAN NATURE— BOOK I 

TO THE INQUIRY CONCERNING 

HUMAN UNDERSTANDING 



w: B. ELKIN, Ph.D. 

ACTING ASSISTANT PROFESSOR OF THEORY AND PRACTICE OF TEACHING 
IN THE UNIVERSITY OF MISSOURI. 



jftcto pork 

THE MACMILLAN COMPANY 

LONDON : MACMILLAN & CO.. Ltd. 

1904 

All rights reserved 



$\^* 



UBRAKY of CONGRESS 
Two Copies Received 

AUG 13 1904 
Oooyrffht Entry 

CLAW $ XXe- Na 

q u ^ o o 

1 C©PY B 




Copyright, 1904 
By THE MACMILLAN COMPANY 



PREFACE. 



This monograph was begun in 1892 as a disserta- 
tion for the degree of Doctor of Philosophy at Cornell 
University. 

Owing to the extensiveness of the literature on the 
subject, the writer's task proved to be a much larger 
one than he had, at first, expected. Although the 
dissertation was finished in 1894, and the main results 
were published in the November number of The Philo- 
sophical Review for that year, the author was not 
quite satisfied with the fruits of his labor. Hence he 
continued the study. The whole has since been re- 
written, and some portions have been amplified. On 
account of the press of other duties, the completion of 
the work has been unavoidably delayed, so that the 
book appears now like one born out of due time. But 
it is hoped that the length of its embryonic period 
has tended only to develop and mature its organic 
structure. 

While Green and Grose's edition of Hume's philo- 
sophical works is the one which was used as the basis 
of study, it was not thought necessary, when giving 
quotations, to follow the text in its archaic forms of 
spelling. Hume's punctuation, of course, has been 
retained. 

In conclusion, the author desires to express his ob- 
ligations to Professor J. E. Creighton, under, whose 
direction the work was originally written, for his 
many valuable criticisms and helpful suggestions; to 

iii 



IV PREFACE. 

Dr. N. E. Truman, on whom fell the laborious task 
of reading the proofs and verifying the references; 
and to The Sage School of Philosophy, which spared 
neither trouble nor expense to procure any books of 
reference that were thought helpful for the work. 

W. B. E. 
Columbia, Mo. 
May 31, 1904. 



CONTENTS. 

CHAPTER I. 

Introduction. 

Page. 

§ 1. Preliminary Remarks 1 

§ 2. Aim 4 

§ 3. The General Relation of the Treatise and In- 
quiry to Hume's other Philosophical Works. . 6 
§ 4. The General Relation of the Treatise and In- 
quiry to each other 10 

I. With regard to Form 10 

II. With regard to Content 16 

8 5. Mode of Procedure 23 



CHAPTER II. 

Hume's Aim, Subject-Matter, and Method. 

§ 6. Hume's Aim 24 

§ 7. Hume's Subject-Matter 41 

§ 8. Hume's Method 45 

CHAPTER III. 

Perceptions: their Nature, and Cause. 

§ 9. The Nature, and Classification of Perceptions. . 50 

§10. The Cause of Perceptions 59 

I. Epistemological 60 

II. Physiological 63 

§11. Conclusion 69 

v 



VI HUME S TREATISE AND INQUIRY. 

CHAPTEE IV. 

Association of Ideas, and Eesult — Complex Ideas. 

Page. 

§12. Association of Ideas 71 

§13. Complex Ideas 77 

I. Philosophical Eelations 77 

II. General or Abstract Ideas 83 

§14. Conclusion 86 

CHAPTEE V. 

Space and Time. 

§15. The Idea of Infinite Divisibility , 89 

§16. The Idea of Space 91 

§17. The Idea of Time 95 

§18. The Treatment of Space and Time in the Inquiry 95 

§19. Conclusion 98 

CHAPTEE VI. 

Theory of Knowledge. 

§20. The Faculties of Mind 102 

§21. Intuitive Knowledge 106 

§22. Demonstrative Knowledge — Mathematics Ill 

I. The Epistemological Exposition 113 

II. The Logical Exposition 117 

III. The Psychological Exposition 123 

IV. Conclusion 124 

§23. The Treatment of Mathematics in the Appendix 125 

§24. The Treatment of Mathematics in the Inquiry. . 126 
§25. The Treatment of Mathematics in Hume's other 

Philosophical Writings 132 

§26. Conclusion 134 



CONTENTS. Vll 

CHAPTEE VII. 

The Idea op Cause and Effect. 

Page. 
§27. Causation the basis of all Eeasoning Concern- 
ing Matters of Fact 140 

§28. Examination of the Idea of Cause and Effect. . . 142 

I. The General Question of Causation 144 

II. The Particular Question of Causation 146 

III. The Idea of Necessary Connection 151 

IV. Conclusion 155 

§29. Some Misconceptions of Hume's Critics 157 

§30. Conclusion 168 

CHAPTEE Vni. 

Belief. 

§31. Belief of Impressions 172 

§32. Belief of Ideas 174 

I. The Exposition of the Treatise 174 

II. The Exposition of the Appendix 175 

III. The Exposition of the Inquiry 180 

§33. The Cause of Belief 190 

§34. Conclusion 192 

CHAPTEE IX. 

Probability, Necessity, and the Eeason of Animals. 

§35. Probability 195 

I. The Account in the Treatise 196 

II. The Account in the Inquiry 198 

III. Conclusion 199 

§36. Liberty and Necessity 201 

§37. The Eeason of Animals 210 



viii hume's treatise and inquiry. 

OHAPTEE X. 

Material Substance and External Existence. 

Page, 

§38. The Idea of Material Substance 216 

§39. The Idea of External Existence 220 

I. The Vulgar Hypothesis 220 

II. The Philosophical Hypothesis 224 

§40. Conclusion 228 

OHAPTEE XI. 

Spiritual Substance, Self, and Personal Identity. 

§41. The Idea of Spiritual Substance 235 

§42. The Idea of Self 237 

§43. The Idea of Personal Identity 239 

§44. The Relation of the Treatise to the Inquiry on 

the Doctrines of Self and Personal Identity. . 242 

§45. Conclusion . 356 

CHAPTEE XII. 

Miracles, a Particular Providence, and a Future Life. 

§46. Miracles 259 

§47. A Particular Providence 266 

§48. A Future Life 275 

CHAPTEE XIII. 
Conclusion. 

§49. Summary 293 

§50. Hume's Philosophical System 295 

I. Epistemology 296 

II. Metaphysics 302 

III. The Philosophy of Eeligion 306 

IV. Conclusion 307 



CONTENTS. IX 

APPENDIX A. 

Page. 

Outline of the Relation of the Treatise to the 
Inquiry 311 

APPENDIX B. 

Bibliography. 

I. Editions and Translations of the Treatise and 

Inquiry 315 

II. Books 316 

III. Periodicals 325 



CHAPTER I. 



INTRODUCTION. 



§ 1. Preliminary Remarks.— The history of Eng- 
lish empirical philosophy is sometimes likened to a 
drama in five acts. In the first act, a system of em- 
piricism is inaugurated by Bacon; in the second and 
third, the dialectic movement is gradually unfolded by 
Hobbes and Locke; in the fourth, the usual compli- 
cations arise through the criticisms and transforma- 
tions of Berkeley ; finally, in the fifth, the scene closes 
with the annihilating catastrophe of Hume. 1 

But as Hume marked the melancholy close of the 
era of sensationalism, he heralded the inspiring dawn 
of a brighter epoch, the era of idealism, and at the 
same time laid the foundation for a synthesis of the 
two, in the more scientific movement of the present 
age. Reid in Scotland and Kant in Germany were 
awakened, almost simultaneously, from their dogmatic 
slumbers, by the subtle and irresistible dialectic of the 
great skeptic. British and German philosophy, how- 
ever, when drifting peacefully toward a euthanasia, 
far from being overwhelmed by the storm of Hume 's 
criticism, were only instigated thereby to make a new 
tack in the never-ending pursuit of speculative truth. 
With felicity no less than impressiveness, Sir William 
Hamilton, in his introductory lecture in 1836, de- 
clared : ' ' The man who gave the whole philosophy of 

1 Cf. Grimm, Zur Geschichte des Erkenntnisproblems von 
Bacon zu Hume, Vorwort. 



2 hume's treatise and inquiry. 

Europe a new impulse and direction, and to whom, 
mediately or immediately, must be referred every sub- 
sequent advance in philosophical speculation, was our 
countryman— David Hume. . . . The skepticism of 
Hume, like an electric spark, sent life through the 
paralyzed opinions; philosophy awoke to renovated 
vigor, and its problems were again to be considered 
in other aspects, and subjected to a more searching 
analysis. ' ' 

It matters little in what manner the position of 
"the last great English philosopher" be designated 
in the history of speculative thought, for his system 
is so unique, and so significant that it will always 
awaken the most profound reflection, as well as merit 
the most candid examination. The study of Hume's 
works, however, is unusually perplexing, and the true 
significance of his philosophy of human nature ex- 
tremely difficult accurately to determine, partly, be- 
cause of the different phases of thought, obscurities, 
ambiguities, and even inconsistencies that appear in 
his writings, but chiefly, because of the twofold ex- 
position of his system. Before a just estimation of 
his philosophy can be arrived at, the more important 
relations subsisting between his philosophical writings 
must be ascertained. It is, therefore, a question of 
much interest what the relations of his chief works 
are to one another. Moreover, this question is also 
one of much importance. For although Hume's in- 
fluence is not perhaps so great now as when James 
Hutchison Stirling wrote: 1 "Hume is our Politics, 
Hume is our Trade, Hume is our Philosophy, Hume is 
our Eeligion,— it wants little but that Hume were even 
The Secret of Hegel, p. lxxiii. 



INTRODUCTION. O 

our Taste," his once striking position in philosophical 
and political thought is still justly prominent. "The 
Treatise of Human Nature and the Critic of Pure 
Reason," remarked his most relentless critic, 1 "taken 
together, form the real bridge between the old world 
of philosophy and the new. They are the essential 
'Propaedeutic,' without which no one is a qualified 
student of modern philosophy." 

Hume's great philosophical work is A Treatise of 
Human Nature. It consists of three books: I, "Of 
the Understanding"; II, "Of the Passions"; III, 
"Of Morals";— intellect, feeling, and will. The first 
two volumes were published in 1739, and the third 
in 1740. It seems, however, that the book was writ- 
ten as early as 1736, when Hume was only twenty- 
five years old. 2 True, in accordance with one of the 
author's distinctive characteristics, it was contin- 
ually revised, up to the very time of publication. 3 Yet 
the changes which were made appear to have dealt 
with form more than with content ; and so far as they 
had reference to content, they were made rather in 
the way of omission, than in the way of development. 4 
But the Treatise of Human Nature awakened no in- 
terest, and received almost no notice; it "fell dead- 
horn from the press,"— to use the expressive words 
of the author. Nevertheless, Hume, thinking that he 

1 Hume's Philosophical Works, I. Green's " Introduction/*' p. 
3. — The references throughout are to the Green and Grose edi- 
tion; I, 1890; II, 1882; III and IV, 1889. Since I, contains 
the Treatise and IV, the Inquiry, in explicit references to these 
works the volume number is not given. 

2 Cf. Burton, Life and Correspondence of David Hume, I, 
pp. 98, 337. 

3 Ibid., I, pp. 62, 63. 

4 Ibid., pp. 63, 64. 



4 . hume's treatise and inquiry. 

had made a mistake in publishing too early, still be- 
lieved that his system of philosophy was of permanent 
value. 1 Hence, he revised the Treatise of Human 
Nature, and published it in much briefer, and more 
popular form. The abbreviated work appeared as 
follows : Philosophical Essays concerning Human Un- 
derstanding, 1748; An Inquiry concerning the Prin- 
ciples of Morals, 1751 ; A Dissertation on the Passions, 
1757. It is only with the first book of each group 
that I propose to deal in the present volume. These 
books will be designated respectively, for the sake of 
convenience and in accordance with common usage, 
the Treatise, and the Inquiry. Reference, of course, 
will be made, from time to time, to Hume's other 
philosophical writings, for the purpose of throwing 
additional light upon the subject, or in order to obtain 
a more comprehensive view of the matter under dis- 
cussion. 

§ 2. Arm.— There is a general impression that the 
position which Hume adopted in the Inquiry is not 
identical with that which he had previously as- 
sumed in the Treatise, and consequently, that the 
philosophical principles of the later work are not 
exactly the same as those of the earlier. It is 
sometimes said that the Inquiry represents the posi- 
tion of the empiricist, or positivist, while the Treatise 
represents the position of the skeptic;— as was re- 
marked recently by one of the most brilliant philo- 
sophical writers of our time: 2 "The Treatise is the 
close of sensationalist philosophy, the Inquiry the be- 
ginning of common sense philosophy." Hence, it is 

1 Hume, My Own Life. 

2 Schurman, The Philosophical Review, Vol. VII, p. 10, n. 



INTRODUCTION. 5 

inferred that the later work, not being so negative as 
the earlier, represents an important change as having 
occurred in the author's thought when his mind be- 
came more mature. 1 On the other hand, some writers 
assert that the position, or standpoint of both books 
is essentially the same. 2 But then, regarding the ex- 
act nature of that position there are again differences 
of opinion; Huxley, 3 for example, insisting that it 
is mainly positive, and Green 4 maintaining that it is 
chiefly negative. If we appeal to the testimony of 
the author himself, this confusion is by no means re- 
moved. For in the advertisement to the second vol- 
ume of the posthumous and authoritative edition of 
his Essays and Treatises on Several Subjects— & vol- 
ume containing the Inquiry,— not only does Hume 
complain that " several writers, who have honored 
the author 's philosophy with answers, have taken care 
to direct all their batteries against the juvenile work, 
which the author never acknowledged," but he con- 
cludes as follows: 5 "Henceforth, the author desires, 
that the following pieces may alone be regarded as 
containing his philosophical sentiments and prin- 
ciples." Yet on another occasion, in a letter to Gil- 

i Cf. Burton, Life, I, pp. 120, 273, 274; Erdmann, History of 
Philosophy, II, p. 128; Falckenberg, Gesch. d. neueren Phil., 
second ed., p. 185, n. 2; Hyslop, Hume's Treatise on Morals, 
p. 17; Hunt, Contemporary Review, Vol. XI, p. 77. 

2 Cf. Green, " Introduction to Hume " ; Huxley, Hume, pp. 
11, 45; Webb, Veil of Isis, p. 71; McCosh, Hist, of Scottish 
Phil., p. 123; Jahn, D. H. Causalitdtstheorie, p. 6. 

3 Hume, pp. 51, 60. 

* Hume's Philosophical Works, Preface to Vol. I, and General 
Introd. 
s Ibid., Ill, p. 38. 



6 hume's treatise and inquiry. 

bert Elliot, he says: 1 "I believe the Philosophical 
Essays [the Inquiry] contain every thing of con- 
sequence relating to the understanding, which you 
would meet with in the Treatise ; and I give you my 
advice against reading the latter. By shortening 
and simplifying the questions, I really render them 
much more complete. Addo dum minuo. The philo- 
sophical principles are the same in both; but I was 
carried away by the heat of youth and invention to 
publish too precipitately." To clear up this ob- 
scurity on the question regarding Hume's exact posi- 
tion in his two chief philosophical works is the aim 
of the present investigation. 

§ 3. The General Relation of the Treatise and In- 
quiry to Hume's other Philosophical Writings.— Be- 
fore entering upon the work in detail, it may be well 
to indicate, in a general way, the relation in which 
these two books stand, (1) to the philosophical writ- 
ings with which they are connected, and (2) to each 
other. The first of these topics will be treated in 
the present section, the second, in the following sec- 
tion. 

As has already been said, it is only the first book 
of each group that falls within the scope of this 
investigation. But here two questions at once sug- 
gest themselves: (1) What are the relations of the 
different books within each group to one another? 
and (2) Can the relation of the Treatise to the In- 
quiry be thoroughly examined without taking account 
also of the books with which these two are respectively 
connected ? Leaving aside the second question for the 
moment, we find a partial answer to the first, in the ad- 

i Burton, Life, I, p. 337 ; cf . p. 98. 



INTRODUCTION. 7 

vertisement to Books I and II of the Treatise of Hu- 
man Nature. ' ' The reader must only observe, ' ' says 
Hume, "that all the subjects I have there planned 
out to myself, are not treated of in these two volumes. 
The subjects of the Understanding and Passions make 
a complete chain of reasoning by themselves; and I 
was willing to take advantage of this natural division, 
in order to try the taste of the public. If I have the 
good fortune to met with success, I shall proceed to 
the examination of Morals, Politics, and Criticism; 
which will complete this Treatise of Human Nature. ' ' 
Here it is seen that Hume regarded Books I and II 
as forming a connected piece, thus practically con- 
stituting one book. But the relation of these two 
volumes to the third is not so close, as the author has 
already indicated, and as he afterwards specifies 
more definitely in the advertisement to Book III. c ' I 
think it proper to inform the public," he says, "that 
though this be a third volume of the Treatise of 
Human Nature, yet it is in some measure independ- 
ent of the other two, and requires not that the reader 
should enter into all the abstract reasonings con- 
tained in them. ... It must only be observed, that 
I continue to make use of the terms, impressions and 
ideas, in the same sense as formerly." From these 
quotations we learn that Hume's philosophy, so far 
as it is presented in the Treatise of Human Nature, 
falls into two general divisions which are, in large 
measure, independent of each other, viz., the phi- 
losophy of the understanding and passions on the one 
hand, and the philosophy of morals on the other. 

In the first section of the Inquiry, the author 
adopts the twofold classification of mental science 



8 hume's treatise and inquiry. 

which the Latins had inherited from the Greeks, 
which the scholastics had popularized, and which pre- 
vailed in occidental philosophy generally, until super- 
seded by the tripartite division of Kant;— a division 
which, through the present dominating influence of 
the biological sciences, is again giving place to the 
Aristotelian classification. Hume states that moral 
philosophy or the science of human nature "may be 
treated after two different manners/ ' abstractly, or 
concretely. 1 And besides making this distinction in 
method, he recognizes a corresponding division of sub- 
ject-matter, viz., the "abstruse" or theoretical phi- 
losophy, and the "easy" or practical; the former be- 
ing conversant with the understanding, and the latter 
with the feelings and will. Thus he asserts : 2 ' ' There 
are many obvious distinctions [between the powers 
and faculties of the mind] , such as those between the 
will and understanding, the imagination and passions, 
which fall within the comprehension of every human 
creature." This same division is implied in the first 
book of the Treatise of Human Nature* and is ex- 
plicitly made in the third book. 4 Consequently, 
Hume's philosophy, so far as it is presented in the 
Treatise of Human Nature, and in the Inquiries and 
Dissertation— thus omitting Politics and Criticism, 
subjects with which we have no direct concern,— 
although falling externally into three divisions, may 
properly be regarded as consisting of two parts, 
theoretical, and practical. Theoretical philosophy is 
treated in Book I of the Treatise of Human Nature, 

1 Pp. 3, 4. 

2 P. 10. 

8 1, p. 543. 

4 II, pp. 235, 236. 



INTRODUCTION. 9 

and in the Inquiry concerning Human Understanding. 
While practical philosophy is treated in Books II and 
III of the Treatise of Human Nature, and in the Dis- 
sertation on the Passions and the Inquiry concerning 
the Principles of Morals. 

We come now to a closer examination of our ques- 
tion. What are the relations of dependence in which 
the books within each group stand to one another? 
An answer is found in the second section of Book I, 
and in the first section of Book II of the Treatise of 
Human Nature. All the perceptions of the mind are 
impressions and ideas. All impressions and ideas 
are those of sensation, and those of reflection. It 
may be said that Book I treats of impressions and 
ideas of sensation, 1 Books II and III of impressions 
and ideas of reflection. Now, since impressions of 
sensation are the perceptions that appear first in the 
mind, while ideas of sensation are but copies of these ; 
and since impressions of reflections arise ' ' either from 
the original impressions, or from their ideas;" 2 the 
treatment of impressions and ideas of reflection will 
be dependent on that of impresions and ideas of sen- 
sation, and not vice versa. Consequently, Books II 
and III are dependent on Book I, but Book I is not 
dependent on Books II and III. In the Inquiries 
and Dissertation the two sections just mentioned are 
omitted. Moreover, among these works there is no 
connection indicated, except the general relation be- 
tween the subjects of which they treat, theoretical 
philosophy, and practical. The Inquiries and Dis- 
sertation were not only written at different times, but 

1 Cf. I, p. 380. 
2 II, p. 76. 



10 hume's treatise and inquiry. 

also in a chronological order different from that of 
the corresponding books of the Treatise of Human 
Nature. They stand, therefore, practically, in no 
relation of dependence upon one another. 

It is now easy to answer the second question, viz., 
Can the relation of the Treatise to the Inquiry prop- 
erly be investigated without a special examination of 
Hume's other philosophical writings? The answer 
is in the affirmative, for the following reasons:— (1) 
Only the first two books of the Treatise of Human 
Nature are closely connected, and regarding them, 
there is a relation of dependence only on the part of 
the second. [(2) The Inquiries and Dissertation are, 
practically, not only separate works, but also inde- 
pendent. (3) The Treatise and Inquiry contain all 
of Hume's epistemology and metaphysics that is of 
permanent or real value for the history of philosophy. 

§ 4. The General Relations of the Treatise and 
Inquiry to each other.— ~We turn now for a moment 
to the general relations in which the Treatise and 
Inquiry stand to each other. These may be consid- 
ered under the two heads of form, and content. 

I. The General Relation of the Treatise to the In- 
quiry with regard to Form. Here two points may 
be noted, style, and arrangement. 

1. Style. Dr. Johnson said that Hume's style was 
not English but French. Johnson, however, was not 
an unbiased critic of Hume. Yet Grose admits that, 
so far as the structure of sentences is concerned, 
Hume was influenced by the literature of France at 
the time he wrote the Treatise. 1 We think it may 
be questioned, whether the French element— if such 

1 III, p. 40. 



INTRODUCTION. 11 

it can be called— in Hume's style was not due more 
to immatureness and originality, than to the influence 
of French literature. The numerous Scotticisms are 
significant of the author's provincialism, as well as of 
his immaturity. Notwithstanding the many expres- 
sions of candor, diffidence, hesitation, and skepticism, 
there is not a little pedantry, superficiality, egotism, 
and dogmatism. ' ' This work, ' ' observed his reviewer, 1 
"abounds throughout with egotisms. The author 
could scarcely use that form of speech more fre- 
quently, if he had written his own Memoirs." Now 
and then, there occurs an expression of insincerity, 
irony, or ambiguous humor, which is extremely puz- 
zling. In some of the repetitions, what is evidently 
meant to be the same thing is expressed so differently 
that it is no longer the same. And besides Hume's 
philosophical mode of expression, there is his habit 
of speaking with "the vulgar." These two forms 
of statement occasionally mingle with each other, or 
at least seem to mingle, with the result that the 
reasoning, at times, becomes inextricably confused. 
Nevertheless, Knight 2 speaks in high appreciation of 
the "admirable literary form" of the Treatise, and 
its unequalled lucidity, both of thought and of ex- 
pression." But with Knight's opinion, respecting 
the lucidity of the Treatise, very few students of 
Hume— and probably none except Scotsmen,— no 
matter how enthusiastic they may be in praise of 
"the master," will be able to concur. 

In the Inquiry, the Scotticisms and French phrase- 
ology have been superseded by the smooth and 

i The Works of the Learned, Nov., 1739. 
2 Hume, p. 26; cf. Burton, Life, I, p. 91. 



12 hume's treatise and inquiry. 

polished diction, so characteristic of Hume's later 
writings. Redundancy, in most eases, has been trans- 
formed to brevity. The depth of thought and labored 
mode of expression of the philosopher have, in large 
measure, given place to the superficiality and elegance 
of the author. Hence, while the Treatise is a difficult 
book to read, the Inquiry is an easy one. Hume thus 
realized, in part at least, the wish that he expressed 
at the close of the first section: " Happy, if we can 
unite the boundaries of the different species of phi- 
losophy, by reconciling profound inquiry with clear- 
ness, and truth with novelty! " 

This change of style, in the later work, is easily ex- 
plained. In the introduction to the Treatise Hume 
remarked: 1 "No man needs ever despair of gaining 
proselytes to the most extravagant hypothesis, who 
has art enough to represent it in any favorable 
colors. " In a letter to Hutcheson, in 1740, he wrote : 2 
"I wish I could discover more fully the particulars 
wherein I have failed. I admire so much the candor 
I have observed in Mr. Locke, yourself, and a very 
few more, that I would be extremely ambitious of 
imitating it, by frankly confessing my errors." In 
the Autobiography he asserted: "I had always en- 
tertained a notion, that my want of success in pub- 
lishing the Treatise of Human Nature, had proceeded 
more from the manner than the matter, and that I 
had been guilty of a very usual indiscretion, in going 
to the press too early.' ' And in the first section of 
the Inquiry 8 he acknowledges that the abstractness of 
philosophical speculations "is no recommendation, but 

1 P. 306. 

2 Burton, Life, I, p. 117. 

3 III, p. 3. 



INTRODUCTION. 13 

rather a disadvantage to them," and that "this diffi- 
culty may perhaps be surmounted by care and art, 
and the avoiding of all unnecessary detail." It is 
not surprising, therefore, that Hume toiled inces- 
santly, with unwearying pains, to acquire a good 
English style; 1 nor is it remarkable that his persistent 
efforts were crowned with the most gratifying suc- 
cess. In due time he became "the one master of 
philosophic English." 2 

Still another cause that might be assigned for the 
change of style, in the Inquiry, was the author's de- 
sire to suit his work to the taste of his readers. 3 For 
the third volume of the Treatise of Human Nature 
was written "in an age, wherein the greatest part 
of men [seemed] agreed to convert reading into an 
amusement, and to reject every thing that [required] 
any considerable degree of attention to be compre- 
hended. "* And the Inquiry was prepared in a 
period which Hume implicitly characterized in a 
similar manner. 5 "Whereas, the first volume of the 
Treatise of Human Nature was written at a time when 
"personal identity" had become "so great a ques- 
tion in philosophy," especially in England, "where 
all the abstruser sciences [were] studied with a pecu- 
liar ardor and application. ' ' 6 

2. Arrangement. Concerning arrangement, the 
writers on Hume, in accordance with their usual cus- 

1 Burton, Life, II, pp. 79-81 ; cf. Tytler, Memoirs of the Life 
and Writings of Henry Home of Karnes, I, pp. 170-173. 

2 III, p. 40. 

3 Cf. Burton, Life, I, pp. 62, 63, 273. 
* II, p. 234. 

s Cf. IV, pp. 4-12. 
«I, p. 539; cf. p. 308. 



14 hume's treatise and inquiry. 

torn, differ diametrically in opinion. Burton states : x 
' ' It has been generally and justly remarked, that the 
Treatise is among the least systematic of philosophical 
works— that it has neither a definite and comprehen- 
sive plan, nor a logical arrangement." On the other 
hand, Adamson declares: 2 "The course of Hume's 
work follows immediately from his fundamental prin- 
ciple, and the several divisions of the Treatise, so far 
as the theoretical portions are concerned, are but its 
logical consequences." While the first view here ex- 
pressed is inaccurate, and the second is inadequate; 
yet in the former, there is an element of truth, as in 
the latter, there is an implication of error. The cor- 
rect view, as indeed one might expect, lies about mid- 
way between the two extremes. 3 The Treatise, as a 
whole, is systematically arranged, but detailed por- 
tions are not. If the work be viewed in its entirety 
methodical arrangement, according to a definite plan, 
is clearly manifest. Thus Part I gives an account of 
the contents of the individual mind, of impressions 
and ideas, or of what Hume calls "the elements" of 
the philosophy of human nature. 4 Part II treats of 
the ideas of space and time, and Part III deals with 
the idea of cause and effect; that is, Part II may be 

1 Life, I, p. 66 ; cf. Ritchie, Life of Hume, p. 305 ; Meinong, 
Hume-Studien, II, p. 27; Knight, Hume, p. 28. 

2 Ency. Brit., ninth ed., art. Hume, p. 352; cf. Jacob, David 
Hume uber die menschUche Natur, I, p. 532; Brede, Der 
Unterschied d. Lehren Humes im Treatise u. im Inquiry, p. 
2, n. 

3 Cf. Grimm, Zur Gesch. d. ErJcenntnisproblems, pp. 573- 
576 ; Jodl, Leoen u. Phil. D. H., p. 200 ; Pfleiderer, Empirismus 
u. SJcepsis in D. H. Phil, p. 132. — Grimm's treatment of this 
question is the best that has yet appeared. 

*I, p. 321. 



INTRODUCTION. 15 

said to treat of the abstract element of human knowl- 
edge, while Part III deals with the concrete element. 
Finally, Part IV explains the ideas of self and sub- 
stance, exhibiting the logical results of the previous 
treatment, and expressing the relation of the knowing 
consciousness to known objects ; that is, it investigates 
the relation of knowledge to the supposed self and ex- 
ternal things, the relation of impressions and ideas as 
cognitive to impressions and ideas as cognized. 1 

There is also a gradual transition between the prin- 
cipal divisions of the work. The last section of Part 
I deals with general ideas, and prepares the way for 
the discussion of the ideas of space and time in Part 

II. The last section of Part II, treating of the ideas 
of existence and external existence, serves as an in- 
troduction to Part III. 2 And the last section of Part 

III, "Of the Keason of Animals," besides containing 
an argument in confirmation of the truth of Hume's 
system, as thus far presented, is at the same time a 
preparation for what follows in Part IV. "When one 
descends to further particulars, however, one finds 
that the minor divisions of the book are often ill- 
arranged, both in their relations to one another, and 
in their internal structure. At one time the reason- 
ing is fragmentary; at another, it is long drawn out, 
stated in different ways, or repeated to weariness. 
Not only are the arguments disproportioned, but 
essential matter is sometimes mingled with non- 
essential; trivial paradoxes are occasionally intro- 
duced, or terms are used with varying meanings, until 
the central thought becomes almost completely ob- 

1 Cf. Adamson, Ency, Brit., art. Hume, p. 352. 
2 1, p. 369. 



16 hume's treatise and inquiry. 

scured by attendant circumstances, or inextricably 
confused through perplexing ambiguities. 

Since the later work is, in some measure, a recast 
of the earlier, the general order of discussion is sim- 
ilar in both. But inasmuch as portions of the Treatise 
are omitted in the Inquiry, and new material is in- 
troduced, while the resulting treatment is clearer, 
freer from ambiguities and contradictions, the ar- 
rangement of the later work is less systematic than 
that of the earlier. The points of transition, formerly 
observable, do not appear in the Inquiry. Abstract 
ideas are treated here only in the last section, and 
then merely incidentally. The ideas of existence and 
external existence are scarcely mentioned. And the 
section on the reason of animals is entirely cut off 
from related topics by new material. These changes, 
except that arising from the introduction of new 
matter— a subject on which more will be said pres- 
ently,— may be accounted for by the abridged form 
of the later work. But then the question immediately 
arises, "Why was the later work abbreviated? This 
inquiry brings us to the next subject for discussion, 
and will be dealt with in the remaining part of the 
present section. 

II. The General Relations of the Treatise to the 
Inquiry with regard to Subject-matter. The Inquiry 
is mainly a restatement, in abbreviated form, of cer- 
tain portions of the Treatise, Parts I and III. To 
Henry Home, in 1737, Hume wrote i 1 " I am sorry I 
am not able to satisfy your curiosity by giving you 
some general notion of the plan upon which I proceed. 
But my opinions are so new, and even some terms 

1 Burton, Life, I, p. 62. 



INTRODUCTION. 17 

that I am obliged to make use of, that I could not 
propose, by any abridgment, to give my system an air 
of likelihood, or so much as make it intelligible. It 
is a thing I have in vain attempted already, at a 
gentleman's request in this place, who thought it 
would help him to comprehend and judge of my 
notions, if he saw them all at once before him. ' ' The 
difficulty here referred to may be the cause why 
Hume, instead of giving a summary or outline of his 
philosophy, in the Inquiry, presents a full statement 
of some subjects, gives an abridgment of others, and 
omits others entirely. Thus Parts I and III are 
largely rewritten. But the only division correspond' 
ing to Parts II and IV is section xii. And this sec- 
tion, although it deals to some extent with nearly all 
the topics that are treated in the corresponding por- 
tions of the earlier work, is by no means an adequate 
abstract or synopsis of them. 

It is interesting to learn from a letter of Hume, in 
1755, to his publisher, Millar, 1 that Part II of the 
Treatise was rewritten. The monograph, however, 
never appeared. As a reason for not publishing this 
revision, Grose 2 suggests that "perhaps the author 
despaired of the subject being popular." Other 
writers on Hume have also expressed their opinions 
on this question. But in general, their views are 
mere conjectures, groundless as they are various. The 
only reason positively known r why this revision of 
Part II was not published, is that given by the author 
himself in a letter to Strahan: 3 "I intended to print 

1 Burton, Life, I, p. 421. 

2 III, p. 60. 

3 Hill, Letters of David Hume to William Strahan, p. 230. — 
For many years it was supposed that Hume's letters to 



18 hume's treatise and inquiry. 

four Dissertations/' he says, "the natural History of 
Religion, on the Passions, on Tragedy, and on the 
metaphysical Principles of Geometry. I sent them 
up to Mr. Millar; but before the last was printed, I 
happened to meet with Lord Stanhope, who was in 
this country, and he convinced me, that either there 
was some defect in the argument or in its per- 
spicuity; I forget which; and I wrote to Mr. Millar, 
that I would not print that Essay." Were one 
controversially inclined, one might now undertake 
to show that the former of the two reasons, here 
mentioned, was the chief one why the "Metaphysical 
Principles of Geometry" was not printed. For de- 
fect in perspicuity, although a sufficient reason why 
the dissertation should not appear as a part of the 
Inquiry, is not a satisfactory explanation why, when 
in the form of an essay, it should have been sup- 
pressed for all time. It is not worth while, however, 
to carry the discussion of this point farther; for the 
fact, that the author forgot whether the defect was in 
the "argument" or in the "perspicuity," tends to 
imply that the essay was open to criticism in both 
these respects. 

Hume also gives a hint why some important por- 
tions of Part IV were omitted in the later work. In 
the appendix to the Treatise 1 he confesses that, on a 
more strict review of the section concerning personal 
identity, he found himself involved in such a laby- 
rinth, that he knew neither "how to correct" his 
Strahan had been destroyed, as it was Strahan's custom not to 
preserve the letters which he received; cf. Burton, Life, II, 
p. 477, n. 2. 

1 I 9 pp. 558, 559; cf, Grimm, Zur Gesch. d. Erkenntnisprob- 
lems, pp. 580, 582. 



INTRODUCTION. 19 

former opinions, nor "how to render them con- 
sistent." This acknowledgment indicates that, soon 
after the publication of the Treatise, Hume per- 
ceived perfectly well one of the main difficulties in- 
herent in his system. It is significant, therefore, that 
in the Inquiry, not merely is the question of personal 
identity omitted, but the other more important sub- 
jects, in the discussion of which inconsistencies or 
absurdities become most apparent, are also either 
omitted entirely, or are only incidentally referred 
to; for example, philosophical relations, space and 
time, mathematics, substance— material and spiritual 
—and an external world. Now all these subjects, 
except philosophical relations, are treated in Parts 
II and IV of the earlier work. The conclusion, 
therefore, is unavoidable, that Hume, when preparing 
the Inquiry for publication, being extremely anxious 
to have his theory of knowledge appear in a favorable 
light before the public, was swayed by the character- 
istic shrewdness of the " canny' ' Scotsman, and pur- 
posely omitted, or left in the background, these diffi- 
cult and perplexing questions. 

Some writers think that Hume omitted, in the In- 
quiry, his doctrine of substance lest it should prej- 
udice the work in the eyes of the public; 1 and others 
assert that he omitted the doctrine of personal ident- 
ity, lest it should shock too severely religious senti- 
ment. 2 The former of these views may contain an 
element of truth, but the latter is entirely erroneous. 
Hume was much more considerate toward the religious 
sentiments of the people when preparing the Treatise 

1 Cf. Selby-Bigge, Hume's Enquiries, Introd. 

2 Cf. Windelband, History of Philosophy, p. 474, n. 1. 



20 hume's treatise and inquiry. 

for publication, than when writing the Inquiry. On 
the former occasion, he withdrew certain obnoxious 
portions, including the argument against miracles, in 
order that the work might give "as little offence as 
possible;" 1 but on the latter, he had no such pru- 
dential scruples when dealing with religious ques- 
tions. 2 It is true, Hume had, in general, much re- 
gard for public opinion; but he rarely manifested 
any concern for what he called "superstition," or 
religious bigotry. 

The omissions mentioned above are partly counter- 
balanced by the introduction of two new sections— x 
and xi-— which deal with miracles and the practical 
consequences of natural religion, and by the trans- 
ference of the discussion on liberty and necessity 
from the second book of the Treatise of Human 
Nature to the Inquiry, where it follows immediately 
the treatment of necessary connection, and forms a 
complete section by itself, section viii. These addi- 
tions to the later work serve to illustrate the practical 
application of Hume's theoretical principles within 
the sphere of morality and religion. And there can 
be little doubt that one of the chief aims of the author 
in making these changes was to induce people to 
examine his philosophical system. He hoped, by 
the publication of the Treatise, to obtain much fame 
on account of the originality, boldness, and practical 
tendencies of his philosophy of human nature. 3 Nat- 
urally, therefore, he was greatly disappointed when 
the book failed to make a noise in the world. But he 

i Burton, Life, I, pp. 63, 64. 

2 Cf. My Own Life; Burton, Life, I, p. 239. 

3 Cf. My Own Life; Burton, Life, I, pp. 64, 108. 



INTRODUCTION. 21 

resolved to profit by his adverse experience. Soon 
after the publication of the first two volumes, he sent 
to Hutcheson, for perusal, the manuscript of the third 
volume, the Treatise of Morals. And in the course of 
his reply to Hutcheson 's suggestions and friendly 
criticism he significantly observed: 1 "I have many 
other reflections to communicate to you ; but it would 
be troublesome. I shall therefore conclude with 
telling you, that I intend to follow your advice in 
altering most of those passages you have remarked as 
defective in point of prudence; though, I must own, 
I think you a little too delicate. Except a man be in 
orders, or be immediately concerned in the instruction 
of youth, I do not think his character depends upon 
his philosophical speculations, as the world is now 
modelled ; and a little liberty seems requisite to bring 
into the public notice a book that is calculated for few 
readers. " Some years later, when writing the In- 
quiry, the author astutely availed himself of " a little 
liberty, ' ' in order to bring the book into public notice. 
It has been commonly thought that Hume mani- 
fested one of the few weak points in his character by 
making a high bid for that notoriety for which his 
soul craved, when in the Inquiry he introduced the 
sections dealing with miracles, providence, and im- 
mortality. 2 But the author of the Treatise of Hu- 
man Nature, in this criticism of popular religious con- 
ceptions, had a much deeper object in view than the 
attainment of mere notoriety. He wished to call the 
attention of readers to the importance of his new 

1 Burton, Life, I, p. 114. 

2 Cf. 8elby-Bigge, Humes Enquiries, Introd. ; Huxley, Hume, 
p. 11; III, p. 36. 



22 hume's treatise and inquiry. 

system. That the scheme was well conceived, and 
that it was eminently successful, later philosophical 
discussion has most abundantly testified. 

The transference of the section on liberty and 
necessity from the second book of the Treatise of 
Human Nature to its appropriate place in the Inquiry 
-—directly after the section on necessary connection- 
may have been prompted somewhat by logical con- 
siderations. But it seems indubitable, because of the 
new mode of treatment which the subject received, 
that the change was made chiefly for the purpose of 
stimulating public curiosity. For the most important 
alteration, in the later presentation, is the greater 
prominence given to the difficulties that, on any theory 
of the will, whether deterministic or libertarian, arise 
in the sphere of philosophy of religion. This dis- 
cussion, along with those on miracles, providence, and 
immortality, Hume undoubtedly thought would at 
once arouse the indignation of "the zealots." But 
he was again grievously disappointed. In the Auto- 
biography he expressed his mortification to find, on 
his return from Italy, "all England in a ferment, on 
account of Dr. Middleton's Free Enquiry," while 
his own performance was "entirely overlooked and 
neglected." Yet in the long run, the author of the 
philosophy of human nature was not far wrong in 
his calculation. He had accurately gauged some of 
the fundamental qualities of mankind. In a few 
years, his bookseller informed him that his "former 
publications (all but the unfortunate Treatise) were 
beginning to be the subject of conversation," and that 
new editions of them were demanded. 1 "Answers 

1 My Own Life. 



INTRODUCTION. 23 

by Reverends, and Right Reverends, came out two or 
three in a year"; and Hume found, "by Dr. War- 
burton's railing, that [his] books were beginning to 
be esteemed in good company." Since then, no 
writer on miracles has neglected to mention the great 
skeptic ; while to refute him has been the ardent aim 
and earnest endeavor of every Christian apologist. 
§ 5. Mode of Procedure.— It is now only necessary 
to add a word with regard to method, in order to con- 
clude this introduction. I propose to proceed top- 
ically, treating each subject of importance separately, 
and following as closely as possible the order of the 
earlier work. In the topical treatment I shall state, 
first, the doctrine of the Treatise on the point in 
question ; secondly, the position of the Inquiry on the 
same subject, noting the differences of view that may 
exist, whether in the way of omission, addition, or 
modification ; and thirdly, indicate, as far as possible, 
the reasons for the changes that appear in the later 
work. 



CHAPTER II. 

hume's aim, subject-matter, and method. 

§ 6. Hume's Aim,.— We now enter upon the sub- 
ject proper of our investigation, viz., the relation of 
Hume's earlier philosophical principles to his later, 
as they are set forth respectively, in the Treatise, and 
in the Inquiry. The first question to determine is 
that of aim. Accordingly, in the present chapter, we 
shall compare the introduction to the Treatise of Hu- 
man Nature with the first section of the Inquiry. 
Throughout, it will be borne in mind, of course, that 
the prefatory remarks in the Treatise are an introduc- 
tion to the science of man, 1 while the first section of 
the Inquiry is an introduction to only one part of the 
science of man, the theoretical part. Much light will 
thus be thrown on some of the differences that ex- 
ist between these two forms of statement, that is, be- 
tween the general introduction to the science of man, 
and the introduction to the theoretical part of the 
science of man. 2 

In the advertisement to the earlier work, Hume 
said that his "design" was sufficiently explained in 
the introduction. Nevertheless, his readers have 
never arrived at any general agreement regarding 
what his design, or purpose was. Thus Mackintosh 
asserts: 3 " [Hume] aimed at proving, not that nothing 

1 1, p. 303. 

2 Cf. p. 7, above. 

3 Dissertation on the Progress of Ethical Philosophy, p. 137; 
cf. Reid's Works, I, p. 183. 

24 



AIM, SUBJECT-MATTER, AND METHOD. 25 

was known, but that nothing could be known;— from 
the structure of the understanding to demonstrate, 
that we are doomed for ever to dwell in absolute and 
universal ignorance. ' ' Priestley i 1 i ' According to 
[Hume's] own very frank confession, his object was 
mere literary reputation. It was not the pursuit of 
truth, or the advancement of virtue or happiness.' ' 
Stirling: 2 " Hume's final aim, of course, is the de- 
struction of what is to him superstition. ' ' Huxley : 3 
1 ' The aim of the Eritik der reinen Vernunft is essen- 
tially the same as that of the Treatise of Human 
Nature, by which indeed Kant was led to develop 
that critical philosophy with which his name and 
fame are indissolubly bound up." Stewart: 4 
" [Hume's] aim is to establish a universal skepticism, 
and to produce in the reader a complete distrust in 
his own faculties." It is unnecessary to multiply 
examples further. Diversity of view on this question 
is doubtless due as much to objective differences in 
the two accounts of Hume's philosophy, as to sub- 
jective differences in the various interpreters. 

The key to the solution of this problem is to be 
found only in Hume's life. From his "earliest in- 
fancy" he exhibited a strong inclination to books and 
letters. When a youth he amused himself in leisure 
hours writing on psychological, ethical, or literary 
subjects. 5 At eighteen, he experienced for, a few 

1 Letters to a Philosophical Unbeliever, p. 125 ; cf. Morris, 
British Thought and Thinkers, p. 238. 

2 Mind, Vol. IX, p. 533; cf. Revue Philosophique, Vol. XII, 
p. 121. 

3 Hume, p. 58; cf. Pfleiderer, Empirismus u. Skepsis, p. 109. 
* Collected Works, I, p. 437; cf. McCosh, Hist, of Scottish 

Phil, pp. 153, 154. 
6 Burton, Life, I, p. 13. 



26 hume's treatise and inquiry. 

months the ecstasy of "philosophical conversion. ' ' 
"There seemed to be opened up to me," he writes, 1 
"a new scene of thought, which transported me be- 
yond measure, and made me, with an ardor natural 
to young men, throw up every other pleasure or 
business to apply [myself] entirely to it." Hume 
now felt that he had a message to deliver to the world. 
He would work a revolution in philosophy or moral 
science, similar to that which Bacon had effected in 
physical science. He resolved on the plan of writing 
a complete system of philosophy, as Spencer did a 
little more than one hundred years later. This proj- 
ect he also carried out, although— since the Treatise 
did not "meet with success"— not without some modi- 
fications, and not quite so thoroughly as he had at 
first intended. For instead of the volumes on politics 
and criticism, which were to form part of the Treatise 
of Human Nature, there appeared only the moral and 
political essays, two essays on religion, and a few 
fragmentary pieces. 

Like every philosopher who has a new doctrine 
to propound, Hume discovered that the current 
theories of knowledge were exceedingly defective. 2 
At the age of twenty-three he wrote: 3 "Every one 
who is acquainted either with the philosophers or 
critics, knows that there is nothing yet established in 
either of these two sciences, and that they contain 
little more than endless disputes, even in the most 
fundamental articles." In the introduction to the 
Treatise, he expresses himself no less strongly. Re- 
garding philosophy, he says: 4 "Principles taken upon 

1 Op. tit., I, p. 31. 

2 Cf. Kant, Kritik d. r. Vernunft, Vorrede. 
•Burton, Life, I, p. 31. *P. 305. 



AIM, SUBJECT-MATTER, AND METHOD. 27 

trust, consequences lamely deduced from them, want 
of coherence in the parts, and of evidence in the 
whole, these are everywhere to be met with in the 
systems of the most eminent philosophers, and seem 
to have drawn disgrace upon philosophy itself. ' ' And 
concerning the sciences, he asserts r 1 ' ' Even the rabble 
without doors may judge from the noise and clamor, 
which they hear, that all goes not well within. There 
is nothing which is not the subject of debate, and in 
which men of learning are not of contrary opinions. 
The most trivial question escapes not our controversy, 
and in the most momentous we are not able to give 
any certain decision." 

Hume now proposes to improve this unfortunate 
state of things by means of his philosophy of human 
nature, or, as he frequently calls it, the science of man. 
In a similar manner had Bacon, Locke, Descartes, 
and many other thinkers hoped, with the aid of phi- 
losophy, to advance the sciences and extend knowl- 
edge. "I cannot forbear," says Hume, 2 "having a 
curiosity to be acquainted with the principles of moral 
good and evil, the nature and foundation of govern- 
ment, and the cause of those several passions and in- 
clinations, which actuate and govern me. ... I am 
concerned for the condition of the learned world, 
which lies under such a deplorable ignorance in all 
these particulars. I feel an ambition to arise in me 
of contributing to the instruction of mankind, and of 
acquiring a name by my inventions and discoveries. ' ' 
All the sciences have a definite relation to human 
nature; in short, human nature is their "capital or 
center. ' ' 3 ' ' Ther.e is no question of importance, whose 
m l T. 305. 2 p. 550. p. 307. 



28 hume's treatise and inquiry. 

decision is not comprized in the science of man ; and 
there is none, which can be decided with any cer- 
tainty, before we become acquainted with that sci- 
ence. ' ' If, therefore, we obtain a mastery of the 
science of man, "we may extend our conquests over 
all those sciences, which more intimately concern hu- 
man life, and may afterwards proceed at leisure to 
discover more fully those, which are the objects of 
mere curiosity. ' n "In pretending, therefore, ' ' he con- 
tinues, "to explain the principles of human nature, 
we in effect propose a complete system of the sciences, 
built on a foundation almost entirely new, and the 
only one upon which they can stand with any se- 
curity.' ' Although Hume here makes extravagant 
claims for his philosophy, there cannot be any doubt 
with regard to his meaning. He will write a treatise 
that will include the sciences of "Logic, Morals, 
Criticism, and Politics"; a treatise that will not only 
serve as a handmaid to all the other sciences, but that 
will at the same time comprehend * ' almost everything, 
which it can any way import us to be acquainted 
with, or which can tend either to the improvement 
or ornament of the human mind. ' ' 2 For he believes 
he has discovered the "new medium," 3 by which truth 
may be established. 4 This thought not only implied 
a brilliant generalization, but also indicated, in a 
striking manner, that practical turn of mind so char- 
acteristic of the philosophers of Scotland. 

In the Inquiry, Hume's aim, on a cursory examina- 

1 P. 307. 2 Ibid. 3 Burton, Life, I, p. 31. 

4 Cf. Aikins, The Philosophy of Hume, p. 35 ; McCosh, Hist. 

of Scottish Phil., pp. 153, 154; Petzholtz, Die Hauptpunkte 

d. H. Erkenntmslehre, p. 8; Falckenberg, Hist, of Modern 

Phil, p. 221. 



AIM, SUBJECT-MATTER, AND METHOD. 29 

tion, seems to be similar to that of the Treatise of 
Human Nature. 1 In the first section, the author re- 
gards knowledge as being in the same imperfect con- 
dition as formerly. The "abstruse philosophers, ' ' 
he says, 2 "think it a reproach to all literature, that 
philosophy should not yet have fixed, beyond contro- 
versy, the foundation of morals, reasoning, and crit- 
icism ; and should for ever talk of truth and falsehood, 
vice and virtue, beauty and deformity, without being 
able to determine the source of these distinctions. ' ' 
Hume does not make such large claims, however, on 
behalf of his philosophy of human nature as he did 
in the earlier work, probably because of disappoint- 
ment at the failure of the Treatise to call forth public 
notice. 3 As early as 1740, in a letter to Hutcheson, 
he said: 4 "I am apt in a cool hour to suspect, in gen- 
eral, that most of my reasonings will be more useful 
by furnishing hints, and exciting people's curiosity, 
than as containing any principles that will augment 
the stock of knowledge, that must pass to future 
ages." Even in passages of the Treatise, he mani- 
fested an apprehension that he would not obtain the 
degree of success he hoped for. He did not expect to 
make "many proselytes" to his view of belief; 5 he 
did not doubt that his sentiments on necessary connec- 
tion would be treated by many of his readers as "ex- 
travagant and ridiculous"; 6 finally, after bewailing 
"the wretched condition, weakness, and disorder of 

1 Cf. Pillon, Psychologie de Hume, p. II. 

2 P. 4, 

3 Cf. Burton, Life, I, pp. 105, 108; Hume, Hist, of England, 
VII, p. 359. 

* Burton, Life, I, p. 118. 

5 P. 416. 6 pp. 461, 468. 



30 hume's treatise and inquiry. 

the f acuities/ ' together with "the impossibility of 
amending or correcting" them, he made the doleful 
confession: 1 "This sudden view of my danger [of 
perishing on the barren rock, on which I am at pres- 
ent], strikes me with melancholy; and as it is usual 
for that passion, above all others, to indulge itself; I 
cannot forbear feeding my despair, with all those 
desponding reflections, which the present subject fur- 
nishes me with in such abundance. ' ' Hume, no doubt, 
did not mean all these forebodings to be taken lit- 
erally. Yet, since the reception given the Treatise 
justified his fears to the full, it is not surprising to 
find a tone of dejection in the introduction to the 
Inquiry. "Abstruse thought and profound re- 
searches," he says, 2 "[nature prohibits], and will 
severely punish, by the pensive melancholy which they 
introduce, by the endless uncertainty in which they 
involve you, and by the cold reception which your 
pretended discoveries shall meet with, when communi- 
cated." 

Nevertheless, as before, Hume thinks that the sci- 
ence of man "has its peculiar merit," and that it will 
contribute to "the entertainment, instruction, and 
reformation of mankind." 3 After distinguishing 
theoretical philosophy from practical, he states that 
the theoretical philosophers "think themselves suffi- 
ciently compensated for the labor of their whole lives, 
if they can discover some hidden truths, which may 
contribute to the instruction of posterity." 4 He as- 
serts that, by employing the maxim of the priority of 

iR 544; cf. Burton, Life, I, p. 105. 
2 P. 6. 3 p. 3. 

'P. 4; cf. IV, p. 253. 



AIM, SUBJECT-MATTER, AND METHOD. 31 

impressions to ideas, "we may reasonably hope to 
remove all disputes, which may arise," concerning 
the nature and reality of ideas. 1 And he maintains 
that the science of man will facilitate the advancement 
of all other sciences ; for theoretical philosophy is sub- 
servient to practical. The latter without the former, 
"can never attain a sufficient degree of exactness in 
its sentiments, precepts, or reasonings"; and a spirit 
of accuracy carries "every art or profession" nearer 
its perfection, rendering it "more subservient to the 
interests of society." Hence, the genius of philos- 
ophy gradually diffuses itself "throughout the whole 
society," and bestows "a similar correctness on every 
art and calling." 2 

Thus far, although Hume, for the reason already 
mentioned, is not so sanguine as formerly in his man- 
ner of expression, there is no difference noticeable be- 
tween the aim of the Treatise of Human Nature and 
the aim of the Inquiry. Presently, however, a new 
aspect of the question emerges. It is objected, in the 
later work, that "metaphysics," that is, "abstruse 
philosophy," is not "properly a science," and that 
"a considerable part of metaphysics" arises either 
from "the fruitless efforts of human vanity," or from 
"the craft of popular superstitions." 3 To this the 
author answers that for the same reason the study of 
human nature is the more necessary. "The only 
method of freeing learning, at once, from these ab- 
struse questions, is to inquire seriously into the nature 
of human understanding, and show, from an exact 
analysis of its powers and capacity, that it is by no 
means fitted for such remote and abstruse subjects. 

*P. 17. 2 pp. 6 , 7. C f t p> 24. 3 P. 8. 



32 hume's treatise and inquiry. 

We must submit to this fatigue, in order to live at 
ease ever after : And must cultivate true metaphysics 
with some care, in order to destroy the false and 
adulterate. ' n And he concludes the section with the 
hope that he may be able to "undermine the founda- 
tions of an abstruse philosophy, which seems to have 
hitherto served only as a shelter to superstition, and 
a cover to absurdity and error. ' ' 

Because of the remarks just quoted, and on account 
of changes in the subject-matter of the Inquiry, many 
of Hume's interpreters have thought that the aim 
of the later work is essentially different from that of 
the earlier. Thus Aikins asserts: 2 "The investiga- 
tion of Human Nature was undertaken in the hope 
that through a knowledge of its principles a founda- 
tion for all the sciences could be laid."— "The In- 
quiry, on the other hand, was written after the bit- 
terly disappointing reception given the Treatise had 
quenched much of Hume's zeal for philosophy and 
driven him to work in other fields of literature. . . . 
Now not only was he addressing a popular audience, 
but he had lost enthusiasm for his subject, and the 
Enquiry concerning Human Understanding suggests 
more than a suspicion that Hume's interest in it was 
more anti-theological than psychological. The intro- 
duction speaks, not of the foundation to be laid for 
all the sciences by the study of human nature, but of 
popular superstitions to be driven from their shelter 
among the brambles of metaphysics." 3 Brede 4 and 
some other critics have expressed a similar view on 
this question. 

1 P. 9. 2 pmi of Hume, p. 35. ^Ilid., p. 49. 

* Der Unterschied d. Lehren H. 9 pp. 45 ff . ; cf. Seth, Scottish 
Philosophy, p. 69. 



AIM, SUBJECT-MATTER, AND METHOD. 33 

Respecting the change in subject-matter a general 
explanation was given in the preceding chapter j 1 fur- 
ther reference to the topic will be made presently. 2 
It should be observed now, that those writers who 
profess to perceive a difference in the aim of the two 
works neglect to note that, in the concluding section 
of the Treatise, Hume supplements the statement of 
his aim given in the general introduction. The aim 
in the introduction, as previously remarked, 3 is the 
general aim of the whole work, the Treatise of Human 
Nature; that aim as modified in the last section of 
Book I is the particular aim of the Treatise, the book 
with which we are dealing. In order, therefore, to 
obtain a correct idea of the aim of the Treatise, it is 
necessary to take account of the concluding section. 
Here Hume, after stating that the sentiments of 
curiosity and ambition are "the origin" of his phi- 
losophy, asserts: 4 "But even suppose that this curios- 
ity and ambition should not transport me into specu- 
lations without the sphere of common life, it would 
necessarily happen, that from my very weakness I 
must be led into such inquiries. It is certain, that 
superstition is much more bold in its systems and 
hypotheses than philosophy; . . . Since, therefore, 
it is almost impossible for the mind of man to rest, 
like those of beasts, in that narrow circle of objects, 
which are the subject of daily conversation and action, 
we ought only to deliberate concerning the choice of 
our guide, and ought to prefer that which is safest 
and most agreeable. And in this respect I make bold 
to recommend philosophy, and shall not scruple to 

*Pp. 16-22. sp p . 36-41. 3p. 24. 

*Pp. 550, 551; cf. IV, p. 406. 
3 



34 hume's treatise and inquiry. 

give it the preference to superstition of every kind or 
denomination. ' ' In these sentences, it is true, the 
author does not explicitly state that one of the ob- 
jects of the Treatise was to overthrow superstition. 
Nevertheless, such an object is evidently implied, both 
here and in other passages of the book. Thus he says 
that, "if we are philosophers, it ought only to be upon 
skeptical principles, and upon an inclination, which 
we feel to the employing ourselves after that man- 
ner." 1 

It may be objected, perhaps, that the aim of the 
later work still appears to be somewhat different from 
that of the earlier. For in the Treatise 2 Hume re- 
peatedly repudiates metaphysics, while in the first 
section of the Inquiry he seems to advocate the pur- 
suit of this study. "But may we not hope that phi- 
losophy," he asks, 3 "if cultivated with care, and en- 
couraged by the attention of the public, may carry 
its researches still farther, and discover, at least in 
some degree, the secret springs and principles, by 
which the human mind is actuated in its operations ? ' ' 
The rejection of a subject of examination, he con- 
tinues, on the ground that it does not lie "within the 
compass of human understanding, "is not desirable; 
nor ought to be embraced too rashly." The differ- 
ence here pointed out, however, is only apparent. 
Hume, in the Inquiry, 4 disavows all truly metaphys- 
ical investigations as fully as in the Treatise. "When 
he expresses the hope that philosophy may discover, 
"at least in some degree, the secret springs and prin- 
ciples, by which the mind is actuated in its opera- 

iP. 550; cf. pp. 308, 309; IV, pp. 27, 28. 
2 Pp. 321, 392, 460. 3 p p . n, 12. 

*Cf. pp. 8, 13, 27, 28, 30, 66, 133. 



AIM, SUBJECT-MATTER, AND METHOD. 35 

tions," he does not expect to discover the nature of 
ultimate or metaphysical principles, but only to 
arrive at an explanation of such principles as "cus- 
tom," or "the association of ideas." These prin- 
ciples he occasionally speaks of as ultimate or original 
qualities of human nature, and he tries— "at least in 
some degree"— to account for the mode of their oper- 
ation. 1 

The fact that Hume, in the introduction to the 
Treatise, reprobates metaphysics, and yet in the first 
section of the Inquiry argues at considerable length 
in defence of metaphysics, is easily explained. He 
uses the term in two very different senses. There is 
the true metaphysics, and the false. The former 
merely means "profound reasonings," or "every 
kind of argument, which is any way abstruse"; 2 
while the latter means rationalistic, or transcendental 
speculations. Rationalistic speculations Hume uni- 
versally condemns; but "profound reasonings" he 
defends in the Treatise as well as in the Inquiry. 3 
Several of the arguments which he adduces in the 
later work, in favor of philosophical studies, appeared 
in the earlier, either in the general introduction, or 
in the concluding section. For instance, in the intro- 
duction to the Inquiry he commends the study of 
"metaphysics" as a means of "safe and harmless 
pleasures"; but in the conclusion to the Treatise he 
asserted: 4 "These sentiments [of curiosity and am- 
bition] spring up naturally in my present disposition; 
and should I endeavor to banish them, by attaching 

*Cf. I, pp. 321, 330; IV, p. 37. 
•I, p. 306; IV, p. 6. 
3 Cf. I, pp. 306-309 ; IV, pp. 6-9. 
*P. 550. 



36 hume's treatise and inquiry. 

myself to any other business or diversion, I feel I 
should be a loser in point of pleasure ; and this is the 
origin of my philosophy. ' ' 

While it is readily admitted that the references, 
in the later work, to the overthrow of superstition, 
are more definite and emphatic than are those in the 
earlier; it must, at the same time, be pointed out that 
they seem to have been made but incidentally. Hume, 
in the Inquiry, when still grieving over the sad fate of 
the Treatise, entered on a special defence of meta- 
physics, or "profound reasonings." In the course of 
the discussion it is asserted, as a serious objection to 
these studies, that "a considerable part of meta- 
physics' ' arises either from "the fruitless efforts of 
human vanity, ' ' or from ' ' the craft of popular super- 
stitions." Whereupon, the author naturally replies, 
that there is then so much the more reason why 
"true" metaphysics should be cultivated with care, 
in order that superstition, or "the false and adulter- 
ate," may be destroyed. That the defence of meta- 
physics is fuller and more systematic in the Inquiry 
than in the Treatise, is doubtless due largely to the 
unfavorable reception accorded to the earlier work. 
Besides, as has been remarked, the first section of the 
Inquiry is an introduction to the theoretical part of 
the science of man, while the corresponding section 
of the Treatise of Human Nature is an introduction 
to the science in general; and this, Hume probably 
thought, did not require any special defence or 
apology. 

The aim of the Treatise, therefore, is found upon 
closer examination to be essentially the same as that 
of the Inquiry, viz., to explain the nature or char- 



AIM, SUBJECT-MATTER, AND METHOD. 37 

acter of human knowledge, through an investigation 
of the contents of the individual mind, in order to 
advance science on the one hand, and to overthrow 
"superstition" and rationalistic philosophy on the 
other. 1 It is true, the aim is stated in a different 
manner in the two works ; but for this difference, rea- 
sons have already been assigned. 2 

In all probability, however, it will still be objected 
that the aim of both works can hardly be the same, 
since the Inquiry contains much new material of a 
polemical character. The force of the objection dis- 
appears at once, when one reflects that Hume had 
already published part of this material in Book II 
of the Treatise of Human Nature? and that he in- 
tended to publish the remainder— all, or at least the 
larger portion— in Book I, but withdrew it at the 
last moment, lest it should give "too much offense" 
as the world was then "disposed." 4 If it be con- 
tended further, that the aim of both works is not 
identical, since much old material is omitted in the 
Inquiry; the obvious reply is, that these omissions 
do not necessarily affect Hume's theory of knowledge. 
Moreover, the essential aim of an abridged work may 
be exactly the same as that of the complete work. But 
finally, it will no doubt be said that the character and 
tone of the two books are fundamentlly different, and 
that the aim must, therefore, be different also. The 
premises in this case are admitted, but not the con- 
clusion—except in part, and here is where the ground 

1 Cf. Pillon, Psychologie de Hume, p. iii. 

2 Pp. 28-31, above. 

3 Cf. p. 22, above. 

* Burton, Life, I, pp. 63, 64. 



38 hume's treatise and inquiry. 

for debate really lies. A few words of explanation, 
however, will make the matter clear. 

In writing a book, an author may be said to have, 
in general, two kinds of aims, intrinsic or universal, 
and extrinsic or individual. The intrinsic aim is the 
desire of the writer to advance knowledge, or promote 
truth, happiness, etc., by means of the principles or 
ideas expressed. The extrinsic, individual, or ac- 
cidental aims are various, such as desire for money, 
fame, notoriety, public good-will, recreation, personal 
pleasure, etc. At one time the intrinsic aim may 
predominate, at another, the extrinsic. Hume, when 
writing each work, was undoubtedly influenced by 
both these classes of motives. And whether the in- 
trinsic or the extrinsic aim predominated, when he 
was writing the Inquiry, cannot easily with positive 
certainty be determined. It is recognized, of course, 
by all competent critics, that in the Treatise the in- 
trinsic aim predominates. But on the other hand, 
it may be conceded that in the Inquiry the extrinsic 
aims, formally at least, appear to preponderate. 

The above admission will perhaps be regarded as 
a virtual surrender of the point in issue. Such, how- 
ever, it is by no means intended to be. It is made 
merely for the sake of clearness and precision, con- 
stituting as it does a new basis for further discussion. 
Hume's primary aim in the Treatise, as has been re- 
peatedly stated, was the presentation of a true theory 
of knowledge which would be of service to science, 
and which would help to overthrow rationalistic meta- 
physics. And his primary aim in the Inquiry, as 
has now been acknowledged, was, possibly, external 
conditions or individual circumstances. But from 



AIM, SUBJECT-MATTER, AND METHOD. 39 

these propositions to draw the conclusion that the 
aim of the Inquiry is essentially different from that of 
the Treatise, before examining at all the ground of 
the difference in the statement of these two aims, 
would not only be premature, but unjustifiable. The 
difference in aim, as above conceded, between the 
two works, is really but apparent, and admits of easy 
explanation. One of Hume's chief objects, in writ- 
ing the Inquiry, was to call the attention of the public 
to the system of philosophy expounded in the Treatise. 
In a letter to Home, in 1742, he said that there was a 
demand for the Essays— Moral and Political. u Iam 
. . . told that Dr. Butler has everywhere recom- 
mended then ; . . . They may prove like dung with 
marl, and bring forward the rest of my philosophy, 
which is of a more durable, though of a harder and 
more stubborn nature. ' n Then he wrote the Inquiry, 
partly at least, for the purpose of helping the Essays 
to bring forward the Treatise. Hence this motive, 
although nominally extrinsic, is properly speaking in- 
trinsic, since Hume's ultimate object was to carry the 
reader beyond the abridged account of his system to 
the complete exposition. And it must finally be con- 
cluded that Hume, when writing the Inquiry, was 
actuated more by intrinsic than by extrinsic motives ; 
for in reality the former were paramount, although 
it may seem that formally the latter predominated. 

Furthermore, it may be observed that the primary 
intrinsic aim of both works is exactly the same, viz., 
the presentation of a true theory of knowledge which 
might be of service to science, 2 and which would sub- 
burton, Life, I, p. 143. 
2 Cf. Orr, David Hume, p. 85. 



40 hume's treatise and inquiry. 

vert rationalistic metaphysics. That this aim is 
sought in a different way in each book is due to 
the different circumstances under which the books 
were written; and from these changes in circum- 
stances there naturally resulted corresponding changes 
in the extrinsic aims. Hume gave a detailed and 
abstract account of his theory of knowledge in the 
Treatise, because he expected to establish a great 
philosophical reputation by means of the work. In 
this object he had apparently failed. Then he ap- 
pealed from the tribunal to the forum, and presented 
in a popular manner the more easy and interesting 
parts of his system. Also, before publishing the 
Treatise, he withdrew some portions of it and modified 
others, in order that it might give ' t as little offence as 
possible," because he intended to present a copy to 
Dr. Butler, and hoped to obtain the applause of the 
learned world. The learned world, however, took 
but little notice. Hence, in the Inquiry, he restored 
these omitted portions, and expressed his views on 
religious questions more freely and less charitably. 
He thought thereby to rouse the learned world up a 
little, and after a while, indeed, he succeeded. 
Hume had now attained to a position such that hos- 
tility from theological quarters tended rather to ad- 
vance his fame than to impede it. Besides, opposi- 
tion from those whose good opinion one does not 
expect to win is often preferable to blank indifference. 
In short, the inevitable conclusion is, that the in- 
trinsic aim of both works is paramount, and also 
identical; but that the extrinsic aims are different. 
This is equivalent to saying that Hume's real object, 
in his philosophical writings, was ever the same; but 



AIM, SUBJECT-MATTER, AND METHOD. 41 

that the means which he adopted for the realization 
of this end varied at different times, according as the 
circumstances seemed to require. This view, it may 
be added, is in perfect accord with the character of 
the man. Though firm in his rights, steadfast in his 
principles, inflexible in his purposes, Hume was es- 
sentially a child of experience, ever willing to learn 
wisdom from the eternal laws of nature, and to con- 
form, in accidentals, to the ways of the world. The 
distinction just made between Hume's intrinsic and 
extrinsic aims, although in itself simple enough, is 
one that has never before been made. Yet by means 
of it, the obscurity which has so long prevailed upon 
the question, whether the aim of the Inquiry is the 
same as that of the Treatise, is entirely removed. 

§7. Hume's Subject-matter.— By subject-matter 
here is meant, not the particular topics which are 
dealt with in the Treatise and Inquiry, but rather 
Hume's philosophy, in its general characteristics, as it 
is presented in these two works. The pTiilosophy of 
human nature, the science of man, or moral philos- 
ophy—all of which terms the author uses synonym- 
ously—comprises all the more important sciences 
which deal with human life or conduct. It is divided 
into theoretical philosophy, and practical; 1 or more 
specifically, into logic, morals, politics, and criticism. 2 
Both these modes of classification are given in the 
Treatise, but only the former in the Inquiry, probably 
because in his later writings Hume did not intend 
to present his complete system. The science of man 
is, therefore, on the one hand, a psychological account 

iIV, p. 3; cf. II, p. 235. 
2 1, pp. 303, 307. 



42 hume's treatise and inquiry. 

of human knowledge, and on the other, a scientific 
treatment of motives and conduct, based on the theory 
of knowledge previously expounded. As already 
stated/ it is only the first of these divisions of the 
science that comes within the scope of this work. 

The philosophy of human nature, as contained in 
the Treatise and Inquiry, rests on two fundamental 
principles, the sensational origin of ideas, and the 
representational theory of knowledge. Hume pro- 
fesses to establish the validity of the former prin- 
ciple by means of proofs; 2 but the latter he simply 
assumes, accepting it without question from preceding 
philosophers. He is thus, at the outset of his specula- 
tions at least, an empiricist, and an idealist. "While 
he is a phenomenalist, he does not hold consistently 
to either the cruder or the finer form of the hypothesis 
of cosmothetic idealism. Occasionally he speaks as if 
knowledge were a tertntm quid interposed between the 
mind and the external object, but again, as if it were 
merely a modification of the mind itself. He accepts 
implicitly Locke's definition of knowledge— the per- 
ception of the agreement or disagreement of two ideas. 
Hence he is equipped with what he regards as the 
only true criterion of certainty. 3 And since he as- 
sumes that the only objects of knowledg'e are states 
of consciousness, or impressions, ideas, and relations, 
he regards the science of man as a propaedeutic to all 
the other sciences. Of course, Hume does not always 
hold consistently to his assumption respecting the 
subjectivity of knowledge. He conforms himself, 

1 P. 4. 2 of. p. 61, below. 

3 Cf. I, pp. 311, 324, 371; IV, pp. 13, 51, 124, 125. 



AIM, SUBJECT-MATTER, AND METHOD. 43 

sometimes consciously, sometimes unconsciously, to 
"the manner" of thinking and speaking with "the 
vulgar. ' n It may be further noted that the Treatise 
and Inquiry contain two very important, and at the 
same time different elements, one logical, the other 
psychological. The logical element is negative in 
tendency, and professes to prove, from an examination 
of the human understanding, that certain supposed 
kinds of knowledge— for example, metaphysics— are 
impossible. The psychological element, on the other 
hand, is positive in tendency, and undertakes to show, 
in a similar manner as before, that certain kinds of 
knowledge— for example, "a mental geography" — 
are possible. It is sufficient to remark here that both 
these elements, as well as the conflict between them, 
stand out more prominently in the Treatise than in 
the Inquiry. The significance of this difference will 
be dealt with later. 2 

There has been considerable discussion on the ques- 
tion, whether Hume was perfectly sincere in adopting 
from Locke and Berkeley the fundamental principles 
of his system. Mamiani 3 affirms that it is a great 
misconception to think that the author of the Treatise 
was serious. And Hamilton 4 asserts that Hume 
merely took up the conclusions of his predecessors, 
without indorsing them, and demonstrated the im- 
possibility of establishing a philosophical system on 
a theory of pure empiricism. On the other hand, 

il, pp. 491,499; IV, p. 29 n. 

2 Pp. 117-125; 127-132; 299-304. 

3 Simon, Berkeley's Principles of Human Knowledge, App. 
II, p. 194. 

* Discussions, p. 87. 



44 hume's treatise and inquiry. 

Seth declares: 1 " There is no reason to doubt that 
[Hume] accepted in perfect good faith the funda- 
mental positions from which he argued." The chief 
reasons for the former opinion are: (1) The ab- 
surdities into which Hume's reasoning sometimes led 
him; and (2) the numerous admissions which he made 
in the Treatise regarding the probable ineffectiveness 
of his arguments. 2 When these considerations, how- 
ever, are weighed against the serious statements of 
the author in the introduction to his work, in the 
appendix, and in several letters, 3 ther.e can be no 
doubt that the balance of evidence is in favor of the 
latter view. 4 Moreover, it is well known that Reid 
held for many years, in perfectly good faith, essen- 
tially the same philosophical presuppositions as his 
skeptical antagonist. In a letter to Hume in 1763, 
he made the following significant admission: 5 "Your 
system appears to me not only coherent in all its 
parts, but likewise justly deduced from principles 
commonly received among philosophers." The sub- 
sequent remark of Seth, 6 that "in refusing to look 
upon Hume's system as a substantive or serious ac- 
count of the nature of things, we may thus fairly 
claim to be taking him at his own valuation," is ob- 
viously open to criticism. We cannot regard one, nor 
a few of Hume 's statements as a just valuation of his 
system of philosophy, without taking account of the 

1 Scottish Phil, p. 68; cf. Knight, Hume, p. 130; Mill, Ex- 
amination of Hamilton, p. 554; Orr, David Hume, pp. 94-101. 
*Cf. pp. 416, 461, 468, 544. 
s Burton, Life, I, pp. 31, 62, 65, 108. 

* Cf. Mind, Vol. XI, p. 269. 
5 Burton, Life, II, p. 155. 

* Scottish Phil, p. 70. 



AIM, SUBJECT-MATTER, AND METHOD. 45 

circumstances under which they were made, and with- 
out giving due consideration also to counter state- 
ments, when such, of a directly opposite nature and 
tendency, appear in his writings. Orr's estimation, on 
this question, is the true one. " There is abundant 
evidence/' he says, 1 "that Hume regarded himself as 
an original discoverer in philosophy. He speaks re- 
peatedly and complacently of 'my system.' He is 
confident that he has succeeded where others had 
failed in establishing the theory of human nature 
upon a just foundation." 

§ 8. Hume's Method.— While the subject-matter 
of Hume's philosophy is but vaguely defined in 
the title of his chief work— A Treatise of Human 
Nature,— the method is clearly indicated— "An at- 
tempt to introduce the experimental method of rea- 
soning into moral subjects." Nevertheless, differ- 
ent opinions have been expressed concerning it 
The view of Morris, 3 viz., that Hume's method is 
"the method of empirical psychology," derived 
from that of "physical inductive science," is sub- 
stantially correct. For by experimental method 
Hume meant simply the scientific or inductive method, 
as this is now generally understood. It is no aston- 
ishing reflection to consider, he says, 4 "that the ap- 
plication of experimental philosophy to moral sub- 
jects should come after that to natural at the distance 
of above a whole century; since we find in fact, that 
there was about the same interval betwixt the origins 

1 David Hume, p. 104. 

2 Cf. Long, Ueber Hume's Lehre v. d. Ideen u. d. Substance, 
p. 37; Hodgson, The Philosophy of Reflection, I, p. 239. 

3 British Thought and Thinkers, pp. 247, 253. 
^ P. 308; cf. IV, p. 174. 



2 



46 hume's treatise and inquiry. 

of these sciences; and that reckoning from Thales 
to Socrates, the space of time is nearly equal to that 
betwixt My Lord Bacon and some late philosophers in 
England, 1 who have begun to put the science of man 
on a new footing, and have engaged the attention, and 
have excited the curiosity of the public. " He thinks 
it evident, "that the essence of the mind being equally 
unknown to us with that of external bodies, it must 
be equally impossible to form any notion of its powers 
and qualities otherwise than from careful and exact 
experiments, and the observation of those particular 
effects, which result from its different circumstances 
and situations." 2 Hume thus includes, under the 
term experimental method, observation of one's own 
mind, and observation of other minds, human and 
animal, in so far as the nature of mental states and 
processes can be subjectively perceived, interpreted 
by conduct, or disclosed by a study of physiology. 
He employs not merely the ordinary method of em- 
pirical psychology in its two aspects, subjective and 
objective, but also, to some extent, the comparative, 
genetic, and historical methods. 3 "The experimental 
method" is not to be confused, of course, with the 
method of experimentation as now employed in what 
is commonly called the "new psychology." For 
although Hume resorted at times to experiment, in 
order to confirm, or to illustrate his reasoning, and 

i " Mr. Locke, my Lord Shaftsbury, Dr. Mandeville, Mr. 
Hutchinson, Dr. Butler, etc." — The space of time is not so 
nearly equal as Hume would represent, being from Thales 
(640 or 625) to Socrates (469) 171 (or 156) years, and 
from Bacon to Locke 71 years. 

2 P. 308. 

3 Cf. I, pp. 364, 365, 468, 469. 



AIM, SUBJECT-MATTER, AND METHOD. 47 

declared that "all our perceptions are dependent on 
our organs, and the disposition of our nerves and 
animal spirits/' 1 he was after all but a worthy fore- 
runner of the modern school of experimental psy- 
chologists. 

In the Inquiry also, Hume emphasizes the experi- 
mental or scientific method. In the first section he 
says that "the only method of freeing learning" from 
abstruse metaphysical questions "is to inquire seri- 
ously into the nature of human understanding, and 
show, from an exact analysis of its powers and capac- 
ity, that it is by no means fitted for such remote and 
abstruse subjects." 2 It will be noted, however, that, 
in addition to this statement, he asserts: 3 "Accurate 
and just reasoning is the only catholic remedy, fitted 
for all persons and all dispositions; and is alone able 
to subvert that abstruse philosophy and metaphysical 
jargon, which, being mixed up with popular super- 
stition, renders it in a manner impenetrable to care- 
less reasoners, and gives it the air of science and 
wisdom." Also in the twelfth section he affirms: 4 
"To begin with clear and self-evident principles, to 
advance by timorous and sure steps, to review fre- 
quently our conclusions, and examine accurately all 
their consequences; though by these means we shall 
make both a slow and a short progress in our systems ; 
are the only methods, by which we can ever hope to 
reach truth, and attain a perfect stability and cer- 
tainty in our determinations." These last two pas- 
sages, if interpreted with strict literalness, are incon- 
sistent with Hume's former statements; for here he 
seems to abandon the inductive method of the scien- 

iP. 498. 2 p. g. 3 p. ma. i P. 123. 



48 hume's treatise and inquiry. 

tists, and to adopt the deductive method of the phi- 
losophers. But the truth of the matter is that the 
"accurate and just reasoning" which is spoken of in 
the first passage, is conversant with matters of fact ; 
and the "clear and self-evident principles' 9 which are 
referred to in the second, are arrived at by means of 
induction. Although Hume, in both works, 1 seemed 
to make certain assumptions, and then reasoned from 
these according to the deductive method, yet in most 
cases, these assumptions are ultimately based, im- 
plicitly at least, on observation and experiment. In 
the Inquiry, the author did not discard, nor even sub- 
ordinate his experimental method. For the result of 
his investigation is but a "mental geography, or de- 
lineation of the distinct parts and powers of the 
mind" f that is, a description of impressions and their 
copies, in their coexistence and succession. Like- 
wise, without adopting any of the distinctive methods 
of experimental psychology, he introduced, as in the 
Treatise, a few experiments in the psychology of sen- 
sation, in order to prove, or to illustrate his argu- 
ments. 3 

It is obvious, therefore, that Hume adopts the scien- 
tific method in both works. The deductive element 
of this method although perhaps not more generally 
employed in the later work than in the earlier, is more 
fully recognized in the first section of the Inquiry than 
in the introduction to the Treatise of Human Nature. 
This change may be explained, in part, on psycholog- 
ical grounds ; Hume at first expected to obtain extra- 
ordinary results from the use of his experimental 

i Of. I, pp. 324, 326, 339; IV, pp. 13-15, 124, 125. 

2 P. 10; cf. pp. 15, 17. 
Cf. IV, pp. 15, 124, 125. 



AIM, SUBJECT-MATTER, AND METHOD. 49 

method. But the change is probably due, in the 
main, to the difference in subject-matter of the two 
introductions; the one being an introduction to the 
science of man, the other an introduction to the 
theoretical part of the science. Hence, when the au- 
thor afterwards takes up the discussion of practical 
philosophy, in the Inquiry concerning the Principles 
of Morals, he again emphasizes the importance of the 
inductive element. Regarding the nature of moral 
distinctions he asserts: 1 "As this is a question of fact, 
not of abstract science, we can only expect success, 
by following the experimental method, and deducing 
general maxims from a comparison of particular in- 
stances." Hume designated the Treatise of Human 
Nature, "An attempt to introduce the experimental 
method of reasoning into moral subjects," because in 
the work he employed the inductive method of the 
natural scientists, rather than the deductive method 
of the rationalistic philosophers. This method he 
followed in the Inquiry in a like manner, and sub- 
stantially to the same extent as in the Treatise, 
i IV, p. 174. 



CHAPTER III. 

PERCEPTIONS: THEIR NATURE, AND CAUSE. 

§ 9. The Nature and Classification of Perceptions. 
-—Although Hume, in his psychology, adopted an 
atomistic view of mind, he did not carry out his 
analysis of the concrete phenomena of consciousness 
sufficiently far to enable him to distinguish between 
the purely psychological standpoint, and the epistemo- 
logical. The ultimate elements of consciousness are, 
for him, not merely structural, but also functional. 
While together they constitute the stream of thought, 
each one separately has meaning, it knows. Failure 
to perceive the true significance of this fact has been 
one of the chief reasons why, on the one hand, the 
merits of Hume 's system have seldom been fully real- 
ized, and why, on the other, the philosophy of human 
nature has been subjected to much irrelevant and 
inane criticism. 

In the Treatise, all mental phenomena are called 
perceptions. These are the only objects of human 
knowledge. 1 Although conjoined, they are not con- 
nected, they all are distinct and separable; that is, 
perceptions generally do not exist separately, but they 
all may be thought of as existing separately, and con- 
sequently, may all exist as distinct and separate en- 
tities. 2 They are complex, or, simple, according as 

i Cf. pp. 311, 324, 327, 339, 371, 396, 408, 466, 483, 493, 503, 
518, 523, 558. 

*Cf. pp. 319, 326, 343, 370, 376, 381, 388, 456, 463, 495, 518, 
540, 558, 559. 

50 



PERCEPTIONS: THEIR NATURE, AND CAUSE. 51 

they can, or cannot be resolved into simpler elements. 1 
Perceptions form two general classes, impressions, 
and ideas. Impressions are always the first to appear 
in the mind. Of this Hume gives two proofs: 2 (1) 
" Every simple impression is attended with a corre- 
spondent idea, and every simple idea with a corre- 
spondent impression." (2) "Wherever by any ac- 
cident the faculties, which give rise to any impression, 
are obstructed in their operations [or when the organs 
of sensation have never been put in action to produce 
a particular impression] , not only the impressions are 
lost, but also their correspondent ideas." Hence it 
follows that all ideas are copies of impressions. Sim- 
ple ideas differ from their corresponding impressions 
only through their less degree of force, vivacity, or 
liveliness. 3 But complex ideas differ also in some 
other— although not important— respects from the 
complex impressions from which they were derived; 
for instance, they are less perfect or complete, and. 
their details are more confused. 4 "With regard to 
force or liveliness, impressions and ideas merge into 
each other, or blend by imperceptible degrees, and 
consequently, at times, cannot be distinguished by 
introspection. 5 Impressions are of two kinds, those 
of sensation, and those of reflection. Impressions of 
sensation are those that arise "in the soul originally, 
from unknown causes," by means of the senses, also 
sensations of ' ' heat or cold, thirst or hunger, pleasure 
or pain." Impressions of reflection "arise mostly 

iP. 312; cf. p. 328. 

2 P. 314. 

*Cf. pp. 311, 312, 327, 396, 452. 

4 P. 313; for an apparent contradiction, see II, p. 113. 

5 Pp. 311, 421. 






52 hume's treatise and inquiry. 

from ideas, ' ' but sometimes directly from impressions 
of sensation. 1 They are the passions, emotions, de- 
sires, and aversions. 2 There are also two kinds of 
ideas, those of sensation, and those of reflection. 
These correspond, respectively, to the two kinds of 
impressions, being copies of them. 3 And since ideas 
may produce ' i the images of themselves in new ideas, ' ' 
there arise "secondary ideas, which are images of the 
primary." 4 Besides the classification of ideas into 
those of sensation and those of reflection, there is an- 
other division into those of memory, and those of 
imagination. Ideas of memory differ from those 
of imagination by their fixed order of appearance in 
the mind, and by their greater degree of force, 
vivacity, or liveliness. 5 

Probably through ignorance of continental philos- 
ophy, Hume mistakenly expresses the opinion that the 
distinction which he makes between impressions and 
ideas settles the controversy concerning innate ideas. 
Hence, he regards all impressions as innate, and all 
ideas as not innate. 6 In the case of different shades 
of color, for example, blue, he admits an exception to 
his general principle that impressions always precede 
their corresponding ideas, but thinks the instance is 
so singular that the general maxim need not be 
altered. 7 True, a similar exception may be observed 
in the degrees of every distinct class of sensations— 
as indeed Hume seems to imply, 8 — not only in the 

iP. 311; cf. II, p. 76. 

2 Pp. 316, 317, 324, 340. 

3 P. 317. <P. 316. 

s P. 317, 318, 386, 387, 407, 409, 545. 
6 1, p. 316. il, p. 315. 

si, p. 315; cf. IV, p. 16. 



PERCEPTIONS: THEIR NATURE, AND CAUSE. 53 

sphere of color, but also in that of sound, taste, etc. 
These instances, however, strictly speaking, are only 
apparent exceptions to Hume's maxim. The differ- 
ent shades of blue are but different degrees of gray, 
or of brightness, mixed with the color tone. And 
ideas may be increased or diminished in quantity or 
in intensity by the imagination alone. 

Of the three sections which originally dealt with 
these topics, only one appears in the Inquiry. The 
two entitled, "Division of the Subject," and "Of 
the Ideas of the Memory and Imagination' ' are en- 
tirely omitted. These omissions were doubtless made 
for the sake of brevity, and do not seem to be signifi- 
cant. Some of Hume's critics, however, have thought 
otherwise. Their views will be examined presently, 
after the points on which there is no controversy have 
been stated. As in the Treatise, all mental phenomena 
are called perceptions. These are the only objects 
of knowledge. 1 Perceptions are conjoined, but not 
connected; they all may be regarded as distinct and 
separate existences. 2 Perceptions fall into two classes, 
impressions, and ideas. That impressions are the 
first to appear in the mind, the same two proofs are 
given as formerly. 3 Hence, all ideas are copied from 
impressions, and differ from them only in degree of 
force, vivacity, or liveliness. 4 The exception to the 
general rule,— that all simple ideas are eopies of im- 
pressions,— is noted as before in the case of color. 5 
And the controversy on innate ideas is supposed to 
be settled by the decision that all impressions are 

i Cf. pp. 13, 15, 51, 52, 61, 64, 125. 

*Cf. pp. 27, 61, 90, 126, 134. 3 P. 15. 

*Pp. 13, 14, 17; cf. II, p. 113. * P. 16. 



54 hume's treatise and inquiry. 

innate, and all ideas are not innate. 1 Thus far, 
there is complete agreement between both works; on 
some other questions there is ground for discussion. 

With regard to impressions and ideas, Hume as- 
serted in the Treatise that it is impossible at times 
to perceive, by means of introspection, the difference 
between them. "It sometimes happens, that our im- 
pressions are so faint and low, that we cannot dis- 
tinguish them from our ideas. ' ' 2 Yet in the Inquiry 
he says : 3 " [The memory and imagination] may mimic 
or copy the perceptions of the senses ; but they never 
can entirely reach the force and vivacity of the orig- 
inal sentiment. . . . The most lively thought is 
still inferior to the dullest sensation." The contra- 
diction here is only apparent. "What Hume means, 
in the latter passage, is that, under normal conditions 
and as a general rule, "the most lively thought is still 
inferior to the dullest sensation.' ' He grants that 
there are exceptions, for he asserts that when the mind 
is "disordered by disease or madness," impressions 
and ideas become "altogether undistinguishable. " 4 
In the Treatise he made several statements of exactly 
similar import. 5 The position of the earlier work, 
viz., that it is sometimes impossible to distinguish 
impressions from ideas by means of introspection, is 
psychologically correct. And Hume would undoubt- 
edly have expressed the same view in the Inquiry, 
had he treated the subject fully, or had he written 
solely for the philosophers and not also for the public. 

Brede 6 states that the distinction between simple 

*P. 17n. 2 p. 311; cf. p. 421. 

3 P. 13. *P. 13; cf. pp. 57, 124. 

s Pp. 311, 421. 

e Der Unterschied d. Lehren H., p. 30. 



PERCEPTIONS: THEIR NATURE, AND CAUSE. 55 

and complex ideas is omitted in the later work, and 
thinks that this omission is due to Hume's desire not 
to emphasize the separateness of simple ideas, since 
soon after writing the Treatise the author discovered 
that he could not unite the separate ideas so easily as 
he formerly thought he could. It may be admitted 
that simple and complex ideas are not defined in the 
Inquiry. But the cause assigned by Brede is evi- 
dently not the real one. For Hume not only still 
holds that all perceptions are distinct and separate, 
and may be thought of as separate existences, 1 but he 
speaks of simple and complex ideas in a manner 
implying the same distinction as that made in the 
Treatise. Incidentally, he remarks: 2 "Complex ideas 
may, perhaps, be well known by definition, which is 
nothing but an enumeration of those parts or simple 
ideas, that compose them." The difference here 
recognized, between simple and complex ideas, was 
not pointed out with the same fulness and clearness 
of detail as in the earlier work, because the author 
now aimed particularly at conciseness of statement. 
The omission is of no special significance. 

Selby-Bigge 3 asserts that, in the Inquiry, the dis- 
tinction between "impressions of sensation and reflec- 
tion' ' is omitted. But he neglects to mention that 
it is repeatedly assumed. For instance, in section 
vii Hume states: 4 "It seems a proposition, which will 
not admit of much dispute, that all our ideas are 
nothing but copies of our impressions, or, in other 
words, that it is impossible for us to think of any- 

i Cf. I, p. 559; IV, pp. 27, 61, 90, 134. 

2 P. 61; cf. pp. 14, 15, 18. 

* Hume's Enquiries, p. xii. 

*P. 51; cf. pp. 17, 38 n., 40, 52, 53, 61, 64, 65. 



56 hume's treatise and inquiry. 

thing, which we have not antecedently felt, either by 
our external or internal senses." He implies, of 
course, that the impressions and ideas of the internal 
senses are those of reflection, as distinguished from 
sensation. As he said in the earlier work, 1 "the idea 
of necessity" must be derived "from some internal 
impression, or impression of reflection." In fact, 
Hume speaks of impressions and ideas of reflection 
in the same manner, and seems to attribute to them 
the same origin in both books. Thus in the Treatise 
he says : 2 l ' This idea of pleasure or pain, when it re- 
turns upon the soul, produces the new impression of 
desire and aversion, hope and fear, which may prop- 
erly be called impressions of reflection, because de- 
rived from it." And in the Inquiry he asserts: 3 
" [The idea of power] is an idea of reflection, since it 
arises from reflecting on the operations of our own 
mind." Explicit treatment of impressions of reflec- 
tion was omitted, in the later work, simply for the sake 
of brevity, as was explicit mention of them often 
omitted in the earlier, for the same reason. "I shall 
only observe before I proceed any farther, ■ ' remarked 
Hume in the Treatise, 4 "that though the idea of 
cause and effect be derived from the impressions of 
reflection as well as from those of sensation, yet for 
brevity's sake, I commonly mention only the latter 
as the origin of these ideas; though I desire that 
whatever I say of them may also extend to the 
former." It was evidently for a similar reason that 
the classification of primary and secondary ideas was 
not given in the Inquiry. For in the Treatise Hume 
said that the limitation of his maxim of "the priority 
*P. 460. 2 p. 317. 3 P. 53. * P. 380. 



PERCEPTIONS: THEIR NATURE, AND CAUSE. 57 

of impressions to ideas, ' ' arising from the recognition 
of the relation of secondary ideas to primary, was 
"an explanation' ' of his general principle, rather 
than ' ' an exception ' ' to it. 1 

As several writers 2 have pointed out, the distinc- 
tion between the ideas of memory, and those of imagi- 
nation is omitted in the later work. "When dealing 
with this subject Hume is not only indefinite, but also 
inconsistent. In the Treatise ideas of memory are 
differentiated from those of imagination by two char- 
acteristics : 3 their fixed order, and their greater force. 
At first, the former 4 characteristic is regarded as be- 
ing the more important, but afterwards, the latter. 5 
Again, not only may ideas of memory be so vivid, 
that they resemble impressions, and are called im- 
pressions of memory; 6 but they may also degenerate 
to such a degree as to become indistinguishable from 
ideas of imagination. 7 And on the other hand, ideas 
of imagination, through repetition, may become so 
strong and vivid that they are mistaken for ideas of 
memory. 8 Grimm's treatment of this question is ex- 
ceedingly plausible, and is probably the best that has 
been given. His argument, in brief, is as follows: 9 
In the early part of the Treatise, Hume regards 
memory as something self-dependent and entirely 
different from imagination. But in a later section, 

ip. 316. 

2 Of. Pfleiderer, Empirismus u. Skepsis, p. 119 n. ; Brede, Der 
Unterschied d. Lehren H. 9 p. 31; Selby-Bigge, Hume's En- 
quiries, p. xii. 

3 Pp. 317, 318. * P. 318. 

s Pp. 386, 387, 545. epp, 334, 385, 387, 407. 

T P. 387. § Pp. 387, 416, 421. 

9 Zur Gesch. d. Erkenntnisprollems, pp. 452, 453. 



58 hume's treatise and inquiry. 

when he enters more deeply into the nature of knowl 
edge of experience, and particularly of the causa 
connection of things, he develops those defects throug] 
which memory is almost deposed from its peculia 
position, so that it differs from imagination only ii 
degree. On account of these defects, the distinctio] 
between the two faculties, at first somewhat strongl; 
emphasized, loses its chief worth. That may be th 
cause, therefore, why Hume in his second wor" 
neglects to enter upon a discussion of this subjed 
The facts are essentially as Grimm states them, an< 
his conclusion is not entirely without justificatior 
It is certain that Hume, when writing the Inquiry 
was influenced by the desire to avoid the contradic 
tions in the earlier work, and that may have been 
reason why he neglected to give a full treatment o 
the ideas of memory and imagination. And it is pr,ot 
able that he perceived the impossibility of precisel; 
distinguishing between these two classes of ideas, am 
therefore refrained from making the attempt withi: 
the compass of a popular essay. But the chief reaso: 
for these omissions was undoubtedly the author's de 
sire to secure conciseness of statement; since he im 
plicitly distinguishes between the ideas of memor; 
and those of imagination, and assigns to the formei 
in contrast with the latter, the chief functions ascribe* 
to them in the Treatise. "Whenever any object i 
presented to the memory or senses," he says, 1 "j 
immediately, by the force of custom, carries the im 
agination to conceive that object, which is usuall; 
conjoined to it; and this conception is attended wit" 
a feeling or sentiment, different from the loos 
i IV, p. 41; cf. pp. 13, 17, 39, 43. 



PERCEPTIONS: THEIR NATURE, AND CAUSE. 59 

reveries of the fancy." If Hume had revised, or 
rewritten the earlier work, instead of only portions 
of it, all the distinctions formerly made between 
memory and imagination would, in all probability, 
have been expressed in the later. Even the incon- 
sistencies that appear in the fuller statement are 
verbal, rather than real. With care they might have 
been avoided. They cannot, therefore, fairly be re- 
garded as having any specific influence on the author 
when he wrote the Inquiry. 

Concerning the question of the nature and classifi- 
cation of perceptions, it is evident that the position of 
the two works is practically the same. On all the more 
important topics there is perfect agreement. On 
minor points, of course, owing chiefly to omissions 
in the Inquiry, there are some differences observable. 
But these are differences of treatment, not of doctrine. 
Since the distinctions which were explicitly made, in 
the earlier work, are either reasserted, or implied in 
the later, the omissions do not seem to have any 
significant bearing on Hume's philosophical position. 

§ 10. The Cause of Perceptions.— The treatment 
of the cause of perceptions is rendered somewhat diffi- 
cult, owing to the ambiguity attaching to the word 
cause. True, it was one of Hume 's main contentions, 
one of the theses which he especially aimed to prove, 
that cause means only invariable antecedent. 1 ' ' Thus 
upon the whole we may infer," he declares, 2 "that 
when we talk of any being, whether of a superior 
or inferior nature, as endowed with a power or force, 
proportioned to any effect ; when we speak of a neces- 

1 1, pp. 375 and ff.; IV, pp. 51 and ff. 
2 1, p. 457; cf. IV, pp. 60, 61. 



60 hume's treatise and inquiry. 

sary connection betwixt objects, and suppose, that this 
connection depends upon an efficacy or energy, with 
which any of these objects are endowed; in all these 
expressions, so applied, we have really no distinct 
meaning, and make use only of common words, with- 
out any clear and determinate ideas." Hume, how- 
ever, was obliged to use the language at his disposal, 
and not infrequently he speaks of cause as if imply- 
ing by it producing power. Yet if the instances in 
which he seems to use cause in this sense be examined, 
it will often be discovered that the real meaning of the 
word is but invariable antecedent. 1 Having defined 
what he meant by cause, he was at liberty to employ 
the terms he found most convenient for his purpose. 
No doubt, at times he found it convenient to use 
cause in an improper sense, perhaps realized that it 
was impossible to avoid such use. But in these in- 
stances he is inconsistent, and the inconsistency must 
be acknowledged. 

Concerning the cause of perceptions, that is, their 
invariable antecedent, Hume gives two different ac- 
counts. 2 These may be called the epistemological 
explanation, and the physiological, viz., (1) What is 
the cause of perceptions according to the philosophy 
of human nature? (2) What is the cause of percep- 
tions according to natural science ? The two questions 
require separate treatment. 

I. What is the cause of perceptions according to 
Hume's system of philosophy, the epistemological ex- 
planation ? In the Treatise, the author says that the 
impressions of sense arise "in the soul originally, 

i Cf. I, pp. 316, 317, 340, 343, 385; IV, pp. 16, 17, 60, 64, 125. 
2 1, pp. 313, 314. 



PERCEPTIONS: THEIR NATURE, AND CAUSE. 61 

from unknown causes. " When the impressions dis- 
appear, they leave their traces or copies; these are 
ideas of sensation— primary ideas of sensation, from 
which, in turn, may arise secondary ideas. Impres- 
sions and ideas of sensation also give rise to impres- 
sions of reflection— passions, desires, and emotions. 
These latter ' ' are copied by the memory and imagina- 
tion and become ideas [of reflection] ; which perhaps in 
their turn give rise to other impressions and ideas." 1 
The order of genesis then is as follows: impressions 
of sensation, ideas of sensation, impressions of reflec- 
tion, and ideas of reflection; impressions of sensation 
being the cause of ideas of sensation— sometimes also 
the cause of impressions of reflection, 2 — ideas of sen- 
sation the cause of impressions of reflection, and im- 
pressions of reflection the cause of ideas of reflection. 

Although the greater part of this account is omitted 
in the Inquiry, Hume's position may easily be ascer- 
tained. As in the Treatise, he distinguishes between 
impressions and ideas, and states repeatedly that all 
ideas arise from the external or internal senses, that 
is, from sensation and reflection. 3 Thus there is im- 
plied the same classification of perceptions as before ; 
and the impressions of sensation and reflection are, 
respectively, the cause of their corresponding* ideas. 
True, it is not explicitly stated that the impressions 
of reflection, in every instance, arise from impressions 
or ideas of sensation. Grimm 4 suggests that perhaps 
Hume wished thus to escape one of the contradictions 
involved in the earlier work, viz., that of making im- 

il, p. 317. 

2<7/\ I, p. 317; II, pp. 75, 76. 

*Cf. pp. 14, 15, 17, 40, 51, 52, 53, 61, 64, 65. 

* Zur Oesch. d. ErJcenntnisproblems, p. 589. 



62 hume's treatise and inquiry. 

pressions of reflection causally dependent on impres- 
sions of sensation, instead of merely successive in 
time. This reason, however, does not seem to have 
been the real one. For according to Hume, causally 
dependent simply means invariably consequent. In 
this sense, Hume again, in the second book of the 
Treatise of Human Nature, regarded impressions of 
reflection, which he called secondary, as dependent 
on impressions or ideas of sensation, which he called 
original. 1 And in a similar manner, in the Inquiry, 
he not only still holds that ideas are dependent on im- 
pressions—as Grimm indeed admits, 2 — but also that 
the impression of reflection from which the idea of 
cause is derived is dependent on impressions of sensa- 
tion. 3 It seems as if the omission in the Inquiry was 
due to the author's desire for brevity of treatment, 
rather than to any change of view, or endeavor to 
avoid contradictions. 

Thus far, there has been assigned no cause of the im- 
pressions of sensation. Concerning these, in a note 
to the first section of the Treatise, Hume asserts: 4 
' 'By the term of impression I would not be understood 
to express the manner, in which our lively perceptions 
are produced in the soul, but merely the perceptions 
themselves." To this statement there is nothing 
corresponding in the Inquiry, except a note on innate 
ideas, which contains the following sentence: 5 "But 
admitting these terms, impressions and ideas, in the 
sense above explained, and understanding by innate, 
what is original or copied from no precedent percep- 

i II, pp. 75, 76. 

2 Zur Gesch. d. Erkenntnisproblems, p. 559. 

3 Pp. 53, 62, 65; Cf. pp. 14, 15, 17, 40, 51, 52, 61, 64. 

*P. 312. s P. 17. 



PERCEPTIONS: THEIR NATURE, AND CAUSE. 63 

tion, then may we assert, that all our impressions are 
innate, and our ideas not innate." Thus he implies 
that impressions are the cause of ideas, but concerning 
the cause of impressions he has nothing now to say. 
In the second section of the Treatise, however, he de- 
clares: 1 "The examination of our sensations belongs 
more to anatomists and natural philosophers than to 
moral; and therefore shall not at present be entered 
upon." In the Inquiry, there is nothing correspond- 
ing to this statement. The sentence just quoted seems 
to imply that Hume will afterwards deal with impres- 
sions. But as this investigation "belongs more to 
anatomists and natural philosophers than to moral," 
the explanation must be physiological rather than 
epistemological. Hence arises the second question. 

II. "What is the cause of perceptions according to 
natural science, the physiological explanation? As 
already stated, thus far, in neither work, does Hume 
assign any cause of the impressions of sensation. In 
the Treatise, he remarked that the examination of the 
impressions of sense belonged more to anatomists and 
natural philosophers than to moral, and therefore 
should not at present be entered upon. Consequently, 
when he afterwards gives a physiological explanation 
of perceptions, it might naturally be supposed that this 
explanation applies only to impressions. The treat- 
ment, however, is too general to bear this interpreta- 
tion. For when he discusses the subject in Part II, 
and again in Part IV, he speaks, not of the cause of 
impressions, but of the cause of perceptions, includ- 
ing the cause of ideas as well as that of impressions. 
In the Treatise are such passages as the following: 2 

1 P. 317. 2 p. 365. 



64 hume's treatise and inquiry. 

"I shall therefore observe, that as the mind is en- 
dowed with a power of exciting any idea it pleases; 
whenever it dispatches the spirits into that region 
of the brain, in which the idea is placed ; these spirits 
always excite the idea, when they run precisely into 
the proper traces, and rummage that cell, which be- 
longs to the idea."-— " When we press one eye with 
a finger, we immediately perceive all the objects to 
become double. . . . But as we do not attribute a 
continued existence to both these perceptions, and as 
they are both of the same nature, we clearly perceive, 
that all our perceptions are dependent on our organs, 
and the disposition of our nerves and animal spirits. ' n 
These quotations clearly indicate that the physiolog- 
ical cause of perceptions is cerebral and neural proc- 
esses—including, of course, the movements of animal 
spirits. Cerebral and neural processes are the in- 
variable antecedents of perceptions. In still another 
passage Hume declares: 2 "I would answer, that we 
must separate the question concerning the substance 
of the mind from that concerning the cause of its 
thought; and that confining ourselves to the latter 
question we find by the comparing their ideas, that 
thought and motion are different from each other, 
and by experience, that they are constantly united; 
which being all the circumstances, that enter into the 
idea of cause and effect, when applied to the opera- 
tions of matter, we may certainly conclude, that 
motion may be, and actually is, the cause of thought 
and perception." It is true, he admits that this 
conclusion "evidently gives the advantage to the 
materialists above their antagonists." 3 But the ad- 

l P. 498. 2 p. 530. 3 p. 532. 



PERCEPTIONS: THEIR NATURE, AND CAUSE. 65 

mission, standing as it does against several contrary 
statements, 1 has no philosophical importance. 2 It 
probably occurred through the author's over zeal in 
his opposition to the "spiritualists" with their "meta- 
physical entities." 

Although, in the Inquiry, there is no definite answer 
given to the question concerning the physiological 
cause of perceptions, there are some statements which 
contain, at least, a partial answer. In section ii, 3 
Hume admits that, when the mind is "disordered by 
disease or madness," ideas may " arrive at such a 
pitch of vivacity" that they are indistinguishable 
from impressions ; and in section xii, 4 he implies that 
many "perceptions arise not from any thing ex- 
ternal," but from the condition of the organism, or 
from a certain state of the brain or nerves. These 
and other passages 5 of like import clearly mean that 
perceptions are caused, that is, invariably preceded, 
by cerebral and neural processes, or by movements 
of the animal spirits. 6 Statements confirming this 
conclusion may be found in Hume's other writings. 
In the posthumous work, the Dialogues concerning 
Natural Religion, for example, Philo asks: 7 "What 
peculiar privilege has this little agitation of the brain 
which we call thought, that we must thus make it the 
model of the whole universe ? ' ' 

The conclusion now reached, viz., that the physio- 
logical cause of perceptions is cerebral processes, seems 

1 Cf. pp. 385, 546. 2 Of. pp. 532, 533. 

3 P. 13. <P. 125. 

« Cf. pp. 15, 55, 57, 124. 

6 Cf . Huxley, Hume, pp. 76, 78; Porter, Science and Senti- 
ment, p. 311. 
1 1I, p. 396. 
5 



66 hume's treatise and inquiry. 

to be inconsistent with a statement made in the sec- 
ond section of the Treatise, to the effect that impres- 
sions of sense arise in the soul originally "from un- 
known causes." The explanation, however, is not 
difficult. In his account of the physiological cause 
of perceptions, Hume has reference to the immediate 
cause ; hence his answer, neural and cerebral processes. 
But when the further question is raised, what is the 
ultimate cause of perceptions? he has no answer to 
give. True this question, from the philosophical point 
of view, is much more interesting than the previous 
one. But Hume does not attempt to answer it. As he 
has just said, impressions of sense arise in the soul 
originally from unknown causes ; that is, the original, 
or ultimate cause of impressions is unknown. In an- 
other passage also, he declares: 1 "As to those impres- 
sions, which arise from the senses, their ultimate cause 
is, in my opinion, perfectly inexplicable by human 
reason, and it will always be impossible to decide with 
certainty, whether they arise immediately from the 
object, or are produced by the creative power of the 
mind, or are derived from the author of our being.' ' 

In the Inquiry, almost exactly the same position is 
assumed in the first part of the twelfth section. "By 
what argument can it be proved," asks Hume, 2 "that 
the perceptions of the mind must be caused by ex- 
ternal objects, . . . and could not arise either from 
the energy of the mind itself, or from the suggestion 
of some invisible and unknown spirit, or from some 
other cause still more unknown to us?" It is true 
that, in the later work, the author does not draw a dis- 
tinction between the question of the immediate cause, 

1 1, p. 385. 2 p. 125. 



PERCEPTIONS: THEIR NATURE, AND CAUSE. 67 

and that of the ultimate cause of impressions. Never- 
theless, this distinction seems to be implied, when he 
admits that some impressions are produced by neural 
and cerebral processes, or by the condition of the 
bodily organism; 1 and when, at the same time, he 
affirms that it is impossible to tell from whence "the 
perceptions of the mind" arise. 2 Thus Hume leaves 
the metaphysical question of realism and idealism un- 
determined, and asserts that it is indeterminable. It 
is a matter which lies wholly beyond the power of 
human understanding. This is the position of the 
Inquiry as well as of the Treatise. 

Before concluding the discussion, some reference 
should be made to the opinions that have been ex- 
pressed, by interpreters of Hume, regarding his doc- 
trine of the cause of perceptions. Huxley 3 states 
that Hume "fully adopted the conclusion to which 
all that we know of psychological physiology tends, 
that the origin of the elements of consciousness, no 
less than that of all its other states, is to be sought 
in bodily changes, the seat of which can only be placed 
in the brain." At the same time, he asserts that 
"Hume is not quite consistent with himself" respect- 
ing the origin of impressions of sensation. 4 Knight 
takes a somewhat similar view, but he is more reserved 
in the expression of it. He says: 5 " [Hume] suggests 
that, for all that we know to the contrary, material 
changes may be sufficient to produce mental ones, 
but he does not teach this dogmatically." He also 
asserts that Hume is inconsistent in his treatment of 

*Cf. pp. 15, 55, 57, 124. 2 p. 125. 

3 Hume, p. 74. * Hume, p. 72. 

5 Hume, pp. 143, 144; cf. Porter, Science and Sentiment, p. 
311. 



68 hume's treatise and inquiry. 

the subject, " both in the Treatise, and the Inquiry.' ' 
Webb declares: 1 "But though in his psychology 
[Hume] refuses to recognise either the conceptions 
or the principles of efficient causation and essential 
substance, yet in his metaphysics he finds himself 
compelled to admit that our impressions have a cause, 
and thus to recognize with Kant the existence of a 
non-sensuous cause of our sensations." And Seth 2 
affirms that, "Hume cuts short the question of the 
cause of our impressions as a transcendental inquiry. ' ' 
Here are several different, and even contradictory 
statements. One represents that, according to Hume, 
the cause of perceptions is cerebral processes; an- 
other that the author, in both works, contradicts him~ 
self; a third that the cause of impressions is a 
noumenal existence; and still another that the cause 
of impressions, being a transcendental question, is not 
investigated. The inconsistencies in these divergent 
views are accounted for, and at the same time in large 
measure removed, by the interpretation that has just 
been given. It is manifest that Hume recognizes a 
distinction between the immediate cause of perceptions 
and the ultimate cause. He distinguishes between 
the immediate and the ultimate causes of phenomena. 3 
He says of his philosophy, that it "pretends only to 
explain the nature and causes of our perceptions, or 
impressions and ideas." 4 He states that the cause 
of perceptions is motion, movements in the brain or 
nerves, or of the animal spirits. 5 But the "ultimate 

i Veil of Isis, p. 120; cf. pp. 87, 121. 

* Scottish Phil, pp. 46, 48; cf. I, p. 161; Aikins, Phil, of 
Hume, p. 44; Speckmann, Hume's metaphysische SJcepsis, 
p. 24. 

3 Cf. I, p. 546; IV, p. 11. *P. 368. 

*Cf. I, pp. 364, 365, 498, 515. 



PERCEPTIONS: THEIR NATURE, AND CAUSE. 69 

cause" of impressions he regards as "perfectly inex- 
plicable by human reason. ' ' That is to say, the cause 
assigned is the immediate cause, and the cause unas- 
signable is the ultimate one. 

§ 11. Conclusion.— The more important results of 
the discussion may be summarized as follows : 

1. The Nature and Classification of Perceptions. 
According to Hume's philosophy, perceptions are the 
only objects of knowledge. All perceptions may be 
thought of as distinct and separate existences. They 
are of two kinds, impressions, and ideas. Impressions 
of sensation are the original elements, or ultimate 
facts of human experience. From these are derived 
the ideas of sensation. Impressions and ideas of sen- 
sation give rise to impressions of reflection, from 
which in turn are derived the ideas of reflection. On 
all these points the position of both works is the same, 
except that, in the Inquiry, it is not expressly stated 
—although evidently implied— that all impressions 
of reflection are utimately dependent on impressions 
of sensation. In the Treatise, it is stated that "as 
our ideas are images of our impressions, so we can 
form secondary ideas, which are images of the 
primary." 1 But this limitation of his maxim of the 
priority of impressions to ideas, Hume says, "is not, 
properly speaking, an exception to the rule so much 
as an explanation of it." The reference, naturally, 
is omitted in the briefer work. 

The classification of ideas given in the Treatise into 
simple, and complex, is omitted in the Inquiry, but 
the distinction between them is still plainly indi- 
cated. 2 The classification of ideas into those of 

iP. 31G. 2 p. 5i, 



70 hume's treatise and inquiry. 

memory, and those of imagination is also omitted in 
the later work. Yet one of the two distinctive char- 
acteristics of ideas of memory, viz., force and vivacity, 
is expressly attributed to them; and the other, fixed 
order, is implied. 1 

2. The Cause of Perceptions. (1) The cause of 
perceptions, according to the principles of the phi- 
losophy of human nature, that is, the epistemological 
cause, has already been treated under ' ' classification. ' ' 
(2) The physical cause of perceptions is motion in the 
nerves and brain, or of the animal spirits. On this 
point the position of the Inquiry seems to be identical 
with that of the Treatise. Concerning the ultimate 
cause of perceptions, Hume has no explanation to 
offer ; in both the Treatise and Inquiry, he regards it 
as unknown and unknowable. 

i Cf. pp. 17, 41, 43. 



CHAPTER IV. 

ASSOCIATION OF IDEAS AND RESULT — COMPLEX IDEAS. 

§ 12. Association of Ideas.— After it had been 
demonstrated by experimental psychology that there 
is not a special faculty of imagination, strictly speak- 
ing but rather that there are several faculties— that 
instead of imagination, there are imaginations,— it 
was natural to infer that Hume's mind was decidedly 
of the visualizing type. 1 The conclusion, supported 
as it is by strong internal evidence, scarcely admits 
of doubt. Hume originated his system of philosophy 
at a very early age; and as Galton 2 has shown, in 
youth the visualizing imagination is most vivid. The 
imaging activities of mind play a large part in the 
philosophy of human nature. Thus, all the objects of 
knowledge are impressions and their copies. "What- 
ever is clearly conceived may exist; and whatever is 
clearly conceived, after any manner, may exist after 
the same manner. . . . Again, every thing which 
is different, is distinguishable, and every thing which 
is distinguishable, is separable by the imagination. " 3 
It is in his treatment of relations and general ideas, 
however, that Hume's visualizing tendencies become 
most conspicuous. So long as he has to deal only 
with sense impressions, or with ideas possessing a con- 
tent that may be pictured, he has comparatively little 
difficulty. But when he treats a subject-matter that 

1 Cf. Fraser, Am. J. of Psy., Vol. IV, p. 230. 

*3Iind, Vol. V, p. 301. 

»I, p. 518; cf. IV, p. 31. 

71 



72 hume's treatise and inquiry. 

cannot be spread out before the eye of imagination, 
he involves himself in obscurities or contradictions. 
He regards relations, at one time, as qualities of 
ideas, 1 at another, as complex ideas, 2 then as acts of 
comparison, 3 and again as results of comparison. 4 
Philosophers had concluded that the general idea 
man could represent men of all sizes only "by repre- 
senting no particular one at all." 5 But Hume, car- 
ried away by his visualizing imagination, professes to 
prove, "that it is utterly impossible to conceive any 
quantity or quality, without forming a precise notion 
of its degrees." 6 Consequently, he concludes that 
abstract or general ideas are "in themselves, indi- 
vidual, however they may become general in their 
representation. The image in the mind 7 is only that 
of a particular object, though the application of it in 
our reasoning be the same, as if it were universal." 8 

Since Hume assumes that all perceptions are "dis- 
tinct and separable," and may exist separately, every 
distinct perception being "a distinct existence," 9 
one of his first problems is to show the manner in 
which ideas are connected, in order that knowledge 
may be possible. In the Treatise, this connection 
is partially effected by the faculty of memory, which 
produces an "inseparable connection," 10 or rather a 
very strong relation, 11 between ideas remembered. But 
there are also the ideas of imagination to be related. 
If these were ' ' entirely loose and unconnected, chance 
alone would join them"; and the result would not be 

il, pp. 319, 322. 2 1, pp. 321, 322. 

»I, p. 463. *I, pp. 352, 372. 

5 1, p. 326. e i, pp. 326, 327. 

7 The italics are mine. 8 1, p. 328. 

9(7/. I, pp. 319, 326, 518. i°P. 321. " Cf. p. 540. 



ASSOCIATION AND COMPLEX IDEAS. 73 

knowledge, but chaos. 1 Confusion happily is averted 
by means of certain principles of association, which 
relate ideas according to general laws in a regular 
and orderly manner. The principles of connection, 
or laws of association, are three: resemblance, con- 
tiguity, and cause and effect. 2 

Several critics 3 have pointed out that Hume should 
have recognized only two fundamental principles of 
association of ideas, since he later reduced causation 
to a species of contiguity. It seems, however, that 
the author of the Treatise, in the section on associa- 
tion, makes causation coordinate with resemblance 
and contiguity only provisionally; for he asserts: 4 
"As to the connection, which is made by the relation 
of cause and effect, we shall have reason afterwards 
to examine it to the bottom, and therefore shall not 
at present insist upon it." He arrives at his classi- 
fication inductively. And while he admits that re- 
semblance, contiguity, and causation are "neither the 
infallible nor the sole causes" of union among ideas, 
he maintains that they are "the only general prin- 
ciples. ' ' 5 

Hume, moreover, offers a partial explanation of 
the laws of association. He calls them "natural 
relations" in contradistinction to "philosophical rela- 
tions." 6 He also calls them "qualities" of ideas. 
And these qualities of ideas, or uniting principles, 
he regards as "a gentle force," or "kind of Attrac- 
tion, which in the mental world will be found to have 

i P. 319. mid.; cf. II, pp. 82, 101. 

3 Cf. McCosh, Agnosticism of Hume and Huxley, p. 18; 
Brown, Philosophy of the Human Mind, II, p. 229; Mill, 
Analysis of the Phenomena of the Human Mind, I, p. 110. 

*P. 320; cf. I, p. 175. sp, 393. 6 p. 322. 



74 hume's treatise and inquiry. 

as extraordinary effects as in the natural, and to show 
itself in as many and as various forms." 1 In Part 
I 2 of the Treatise, he asserts that the cause of asso- 
ciation must be resolved into "original qualities of 
human nature, ' ' which he does not pretend to explain. 
But in Part II, 3 he alleges that a physiological ex- 
planation of the laws of association might be given, 
by showing "why upon our conception of any idea, 
the animal spirits run into all the contiguous traces 
[or cells, in the brain], and rouse up the other ideas, 
that are related to it." It may be noted that, in 
the opinion of Uhl, 4 Hume is here speaking ironically, 
perhaps with reference to Descartes. On the other 
hand, according to Morris, 5 he professes his utter, 
inability to explain the laws of association. The 
former view is undoubtedly incorrect; but the latter 
is true, in the sense that Hume professes his inability 
to give an ultimate explanation of these laws; he 
lays claim only to suggest a physiological explana- 
tion. 6 

In the early editions of the Inquiry, the treatment 
of association of ideas consisted largely of popular 
illustrations. These were gradually relegated to foot- 
notes, until the discussion in the text became exceed- 
ingly brief. It is now simpler, as well as briefer 
than that in the Treatise. 7 As before, Hume recog- 
nizes three principles of connection among ideas, re- 

1 P. 321. « Ibid. 3 Pp. 364, 365. 

* Die Qrundzilge d. Psychologie D. H., I, p. 29 n. ; cf. Pfleiderer, 
Empirismus u. Skepsis, p. 121 n. 2. 

5 British Thought and Thinkers, p. 248. 

6 Cf. Riehl, Der philosophische Kriticismus, I, p. 153; Lange, 
History of Materialism, II, p. 160. 

* Cf. Burton, Life, I, p. 286. 



ASSOCIATION AND COMPLEX IDEAS. 75 

semblance, contiguity, and cause and effect. He ad- 
mits it may be difficult to prove satisfactorily "that 
this enumeration is complete," but thinks that "the 
more instances we examine, and the more care we 
employ, the more assurance shall we acquire, that the 
enumeration, which we form from the whole, is com- 
plete and entire." 1 Since a separate account of 
memory is not given in the Inquiry, Hume does not 
explicitly represent that faculty as a principle of 
union among ideas ; yet he does so implicitly. 2 More- 
over, in conformity with his treatment of percep- 
tions, 3 he does not now offer a physiological explana- 
tion of the principles of association. With the ex- 
ception of the differences just indicated, which are 
but of minor importance and are easily accounted 
for, the position of both works on the subject of asso- 
ciation of ideas is exactly the same. 

An apparent inconsistency in the two account may 
here perhaps be noted. In the Treatise 4 Hume said 
that resemblance, contiguity, and cause and effect 
were not the "sole causes" of union among ideas; 
but in the Inquiry, 5 he says that these are "the only 
three principles of connection." The discrepancy is 
only verbal. "What the author means, in the later 
work, is that resemblance, contiguity, and cause and 
effect are the only three fundamental principles of 
association. For he immediately adds, in a foot-note, 6 
that "contrast or contrariety is also a connection 
among ideas." But contrast he does not regard as 
a law or principle of association, since he thinks it 
may be considered as "a mixture of causation and 
resemblance." 

iP. 18. 2p p# i7 ? 41^ 43. so/, pp. G5--67 above. 

'P. 393. 5 p. is. *IMd. 



76 hume's treatise and inquiry. 

Selby-Bigge 1 asserts that, "in the treatment of asso- 
ciation/' in the Inquiry, "little is said about causa- 
tion as a principle of association"; while on the other 
hand, Pfleiderer 2 affirms that Hume's excursion on 
association, in the later work, is too prolix. Both 
statements are substantially correct. At the con- 
clusion of the discussion, in the Treatise, Hume re- 
marked: 3 "Nothing is more requisite for a true phi- 
losopher, than to restrain the intemperate desire of 
searching into causes, and having established any 
doctrine on a sufficient number of experiments, rest 
contented with that, when he sees a farther examina- 
tion would lead him into obscure and uncertain specu- 
lations. In that case his inquiry would be much 
better employed in examining the effects than the 
causes of his principle. ' ' Naturally, therefore, in the 
briefer work, after stating that the enumeration of 
the laws of association was "complete and entire," 
he continued: 4 "Instead of entering into a detail of 
this kind, which would lead into many useless sub- 
tilties, we shall consider some of the effects of this 
connection upon the passions and imagination ; where 
we may open a field of speculation more entertaining, 
and perhaps more instructive, than the other. ' ' Then 
followed several illustrations of his principles, as ap- 
plied in history, poetry, and the drama. This ex- 
cursion within the field of literature was transferred, 
in course of time, to foot-notes. Hence, in the early 
editions of the Inquiry the treatment of association 
is prolix, but in the later editions— omitting the foot- 
notes—it is exceedingly brief. With regard to Selby- 

* Hume's Enquiries, p. xii. 

2 Empirismus u, Skepsis, p. 120 n. 

3 P. 321. *P. 19 n . 



ASSOCIATION AND COMPLEX IDEAS. 77 

Bigge 's assertion that little is said, in the later work, 
about causation "as a principle of association/' it 
may be noted that the treatment of causation, as an 
associating principle, was fuller in all the earlier 
editions of the Inquiry than that given in the Treatise. 
As Hume, in the earlier work, stated that causation 
was "the most extensive" 1 of the three principles of 
association, so in all the editions of the later work, 
prior to that of 1777, he affirmed that the relation 
of cause and effect was "the strongest" of all the 
relations, and "the most instructive." 2 The changes 
of treatment, in the Inquiry, were undoubtedly clue 
to the author's desire to present his theory of knowl- 
edge in a popular manner; and the omissions must 
be attributed to his wish for brevity of statement. 

§ 13. Complex Ideas.— The products of the laws 
of association, or of the natural relations are com- 
plex ideas. These are philosophical relations, modes, 
and substances. 3 They may be treated in their order. 

I. Philosophical Relations. It was remarked in 
the last chapter 4 that Hume nowhere distinguishes 
between the standpoint of psychology, and that of 
epistemology. It may be noted now that he fails in 
like manner, in his treatment of relations, to distin- 
guish between purely logical, and psychological pro- 
cesses. This is another source of ambiguity that must 
constantly be kept in mind. In the earlier work, 
the section dealing with relations is exceedingly ob- 
scure, and the several scattered references tend rather 
to befog the reader than to illumine the subject. 
Hume states that complex ideas are "the effects" of 
the natural relations. Soon, however, for natural 

iP. 320. 2 p. 19 n . si, p< 321. * p. 50. 



78 



hume's treatise and inquiry. 



relations he substitutes "principles of union or co- 
hesion" among simple ideas. 1 And principles of 
union, or "qualities" of objects he afterwards speaks 
of as philosophical relations. 2 Philosophical rela- 
tions are distinguished from natural relations in the 
following manner. 3 A natural relation is "that 
quality, by which two ideas are connected together 
in the imagination, and the one naturally introduces 
the other." A philosophical relation is "that partic- 
ular circumstance, in which, even upon the arbitrary 
union of two ideas in the fancy, we may think proper 
to compare them." It will be observed that these 
definitions differ from each other only in degree. But 
Hume, in his treatment of philosophical relations, 
does not confine himself strictly to his definition. He 
speaks of philosophical relation, not only as the source 
of comparison, but also as the result of comparison, 4 
and finally, as the act of comparison. 5 Hence there 
appear now to be three kinds of philosophical rela- 
tions. And as one of these, the results of comparison, 

is afterwards subdivided, 6 
there are five sorts of re- 
lations in all, — four of phi- 
losophical" relations, and 
one of natural. The mat- 
ter will become clear by 
presenting this classifica- 
tion in the schematic form 
of three concentric circles. 7 
In the inner circle are the 
natural relations, resem- 

322, 323. 3P, 322. 

*P. 372. 
128. 




s. of .cowip-fc 



'Pp. 



iP. 321. 

*Pp. 322, 323, 372. 6 P. 463. 

7 Cf. Pfleiderer, Empirismus u. Sleeps is, p 



ASSOCIATION AND COMPLEX IDEAS. 79 

blance, contiguity, and cause and effect. As these 
diminish in strength, so that they do not produce asso- 
ciations naturally, they pass to the middle circle and 
become qualities, or "particular circumstances' ' in 
respect of which two ideas may be compared. 1 Here 
they are joined by four other "particular circum- 
stances,' ' identity, contrariety, proportions in quan- 
tity, and degrees of quality. These seven "particular 
circumstances" are the philosophical relations that are 
purely psychological. They are "the sources" of all 
other philosophical relations, 2 viz., those which are 
logical as well as psychological. This latter class is 
represented by the outer circle. It contains two sub- 
classes, acts of comparison, 3 and results of com- 
parison, 4 corresponding respectively to the concave 
and convex sides of the circle. Finally, there is a 
twofold division of the results of comparison: 5 (1) 
those that "may be changed without any change in 
the ideas," viz., identity, contiguity, and causation; 
(2) those that depend entirely upon the ideas com- 
pared, viz., resemblance, contrariety, proportions in 
quantity, and degrees of quality. 

It is not implied, of course, that Hume had the 
above classification of relations clearly in mind. Nor 
is it probable that, even if he had, he would have 
stated it explicitly. He did not possess the schematiz- 
ing faculty so characteristic of Kant, But he was 
endowed with profound psychological insight, and an 
extraordinary degree of sound common sense, which 
enabled him to seize the chief features of his problem, 
and thus to treat of relation in its most important 
stages of development. True, he did not do this 
quite consistently. The contradictions, however, are 

*P. 322. *Ibid. 3 P. 4G3. *Pp. 322, 372. *P. 372. 



80 hume's treatise and inquiry. 

mostly verbal, apparent rather than real. And when 
these are removed, it must be conceded that his psy- 
chology of relations contains practically all the essen- 
tial elements that are yet to be met with in the most 
scientific treatment of that subject. 

Hume's doctrine of relations has often been criti- 
cised on the ground that ideas of relation are not 
copies of impressions. 1 Huxley even proposed, in 
order to obviate this objection, to amend "Hume's 
primary geography of the mind," by including 
"impressions of relation" among the elementary 
states of consciousness. 2 But Huxley did not have 
sufficient psychological training to enable him to be 
of any service to the Scottish philosopher on this 
occasion. Nor does the latter stand much in need 
of the proffered assistance. Hume, as indeed Seth 
admits, "does not strip his impressions quite bare 
of relations." 3 He recognizes the fact of related- 
ness among perceptions. 4 From this the way is easy 
to "the natural relations," or laws of association. 
He recognizes the fundamental form of association, 
viz., ab — be, 5 when he speaks of "the bond of 
union" among ideas as "some associating quality." 6 
Finally, he arrives at an abstract idea of relation by 
comparing perceptions. "Since equality is a rela- 
tion," he says, 7 "it is not, strictly speaking, a prop- 
erty of the figures themselves, but arises merely from 
the comparison, which the mind makes betwixt them." 

1 Of. Introd., p. 174; Adamson, Ency. Brit., art. Hume, p. 
352; Seth, Scottish Phil., pp. 54, 55; Grimm. Zur. Gesch. d. 
Erkenntnisproblems, pp. 592, 593; Pillon, Psychologie de 
Hume, p. xiv. 

2 Hume, p. 69. * Scottish Phil, p. 54. * I, p. 319. 
5 Cf. Titchener, Primer of Psychology, p. 131. 

6 1, p. 319. 7 \ } p# 352; C f. pp. 341, 463. 



ASSOCIATION AND COMPLEX IDEAS. 81 

Thus Hume advances from the relatedness of impres- 
sions and ideas, through association and comparison 
to the abstract idea of relation. 

In the Inquiry, the section on philosophical rela- 
tions is entirely omitted. Hume's division of com- 
plex ideas into relations, modes, and substances, be- 
ing an inheritance from Locke, is not transmitted 
to the later work; partly, because it is not essential 
to his main purpose, and partly, because he has now 
largely outgrown Locke's influence. 1 For his former 
classification of complex ideas he substitutes the two- 
fold division of "the objects of human reason or in- 
quiry," 2 viz., relations of ideas, and matters of fact, 
without stating whether the relations thus involved 
are natural or philosophical. Modes, or general 
ideas, and substances he treats incidentally; but 
philosophical relations he recognizes only indirectly, 3 
without explicitly mentioning. 

Pfleiderer 4 suggests, as a reason for this omission 
of a treatment of philosophical relations, that the 
peculiar activity of mind betrayed by the multitude 
of relations and comparisons, in the Treatise, was 
inconsistent with Hume's theory of psychological 
atomism. The argument, however, has no weight. 
Activities of mind, that is, activities of perceptions, 
gave Hume no concern— and rightly— in his exposi- 
tion of relations. On the other hand, several am- 
biguities and some inconsistencies arose through his 
speaking of philosophical relations as the ground of 
comparison, as acts of comparison, and as results of 

i Cf. I, pp. 308, 342; IV, p. 17 n. 

2 P. 20. 3 Pp. 63, 64, 79. 

* Empirismus u. Skepsis, pp. 128, 129 ; cf. Brede, Der Unter- 
scMed d. Lehren H., p. 33. 
6 



82 hume's treatise and inquiry. 

comparison, without distinguishing between psycho- 
logical relations and logical. By neglecting to treat 
this subject in the Inquiry, the author avoided 
many vexatious embarrassments. Besides, the ex- 
plicit distinction between natural, and philosophical 
relations may have been omitted because, not only is 
there no real line of separation between them, but in 
the earlier work there arose at once a confusion be- 
tween the relations of identity and resemblance, and 
also a tendency for the three natural relations to 
become indistinguishable from the three philosophical 
relations that might change "without any change in 
the ideas.' ' Moreover, shortly after publishing the 
Treatise, Hume became more conscious than form- 
erly of the difficulties involved in his system, through 
the inadequacy of relations satisfactorily to unite 
successive perceptions in consciousness, and thus ex- 
plain personal identity. 1 This discovery, and like- 
wise the author's well-known desire to present the 
more important parts of his philosophy in a popular 
manner furnish additional reasons for the omission in 
the briefer work of a discussion so obscure, intricate, 
and even self-contradictory as that on philosophical 
relations. 2 

Yet this omission does not necessarily imply any 
important change in Hume's doctrine. Minor 
changes it undoubtedly signifies, but essential ones 
obviously not. Incidental references confirm this 
conclusion. Thus, in the twofold definition of cause, 3 
Hume implicitly admits a distinction between natural 

1 1, p. 559. 

2 Cf. Grimm, Zur Gesch. d. Erlcenntnisprollems, pp. 458, 459, 
576; Brede, Der Unterschied d. LeJiren H., pp. 32, 33. 
3 IV, pp. 63, 64, 79. 



ASSOCIATION AND COMPLEX IDEAS. 83 

relations and philosophical. And the division of 
"the objects of human reason' 71 into relations of 
ideas and matters of fact, implies a distinction be- 
tween the two classes of philosophical relations ; for it 
corresponds in large measure, to the twofold division 
of these relations which is given in the Treatise, viz., 
into those that depend entirely upon the ideas com- 
pared, and those that may change without any change 
in the ideas. Hume now avoids all his former diffi- 
culties by substituting, for the twofold division of 
philosophical relations, the simple division of objects 
of reasoning into relations of ideas, and matters of 
fact, without explicitly stating whether the relations 
thus involved are natural, or philosophical. 

II. General Ideas. Besides philosophical rela- 
tions, the products of the laws of association are 
substances, and modes— including general ideas. The 
idea of substance will be dealt with later, along with 
that of external existence. And with regard to 
modes, the first question of interest is Hume 's doctrine 
of abstract ideas. 

Hume did not distinguish between abstract idea 
proper, and general idea, that is, between the idea of 
an attribute, and the idea of a common attribute, or 
between the idea of a part of an object, considered 
as a part, and the idea of a number of objects pos- 
sessing common qualities. Following the example of 
Locke, he used the term abstract idea for any notion 
which is the result of abstraction and generalization. 
In this way he is accountable for much of the con- 
fusion which has prevailed in philosophical discus- 
sion, and which to a certain extent still continues, 
regarding the use of the terms abstract and general. 

1 IV, p. 20; of. I, p. 423; II, p. 240. 



84 hume's treatise and inquiry. 

It is unnecessary to go into the details of Hume's 
argument, in the Treatise, to prove that general ideas, 
so-called, are always particular. The conclusion fol- 
lows directly from his fundamental principles: AH 
simple impressions are distinct existences; and all 
simple ideas are but copies of simple impressions, 
while all complex ideas are merely combinations of 
simple ideas. Hence, every idea must be determined 
in its degree "both of quantity and quality"; that 
is, all ideas are particular. 1 But although all ideas 
are particular, those that have a common name and 
are thus called general, may represent successively 
a number of individuals, "in such an imperfect man- 
ner as may serve the purposes of life." This they 
do by means of resemblance and custom. 2 

In the appendix 3 Hume added a brief note on gen- 
eral ideas, merely in order to further explain his doc- 
trine, not to indicate any change of view. And in 
the Inquiry, in the few incidental references which 
he makes to this subject, he adopts the same position 
as he did in the Treatise. Thus in the twelfth sec- 
tion, after pointing out that the primary, as well as 
the secondary qualities of objects are perceptions in 
the mind, he affirms: 4 "Nothing can save us from 
this conclusion, but the asserting, that the ideas of 
those primary qualities are attained by Abstraction; 
an opinion, which, if we examine it accurately, we 
shall find to be unintelligible, and even absurd. An 
extension, that is neither tangible nor visible, can- 
not possibly be conceived: And a tangible or visible 
extension, which is neither hard nor soft, white nor 
black, is equally beyond the reach of human concep- 

i Pp. 326, 327. 2 p. 328. 3 i j p . 328 n. * P. 127. 



ASSOCIATION AND COMPLEX IDEAS. 85 

tion. Let any man try to conceive a triangle in 
general. . . . and lie will soon perceive the ab- 
surdity of all the scholastic notions with regard to 
abstraction and general ideas." Again, in a note re- 
ferring to the contradictions in mathematics arising 
from the supposed infinite divisibility of quantity 
and number, he adds: 1 "It seems to me not impos- 
sible to avoid these absurdities and contradictions, if 
it be admitted, that there is no such thing as abstract 
or general ideas, properly speaking ; but that all gen- 
eral ideas are, in reality, nothing but particular ones, 
attached to a general term, which recalls, upon occas- 
ion, other particular ones, that resemble, in certain 
circumstances, the idea, present to the mind." On 
the question of general ideas, therefore, the position 
of the Inquiry is identical with that of the Treatise. 
It has been much debated whether Hume's doctrine 
of general ideas is the same in both works, and also 
whether it is the same as that of Berkeley. On the 
latter point Meinong's view, 2 rather than Pfleiderer 's, 3 
is undoubtedly the more correct. Berkeley 4 does not 
deny absolutely that there are "general ideas," but 
only "that there are any abstract general ideas." 
Hume, on the other hand, is an ultra-Nominalist. 
On the former point, however, Meyer, 5 rather than 
Meinong, 6 holds the truer opinion. No change in 
Hume's doctrine of abstract or general notions is dis- 

*P. 129 n. 

2 Hume-Studien, I, pp. 218, 219; cf. Mind, Vol. Ill, p. 387. 
* Empirismus u. Skepsis, p. 126. 
4 Fraser, Selections from Berkeley, p. 21. 
5 H. und B. PHI. der Mathematik, pp. 38, 39; cf. Mind, Vol. 
XX, p. 266. 

6 Hume-Studien, I, p. 259. 



86 hume's treatise and inquiry. 

coverable in the Inquiry. Of course Hume's treat- 
ment, in the earlier work, of what he calls "a dis- 
tinction of reason," may be looked upon as a 
concession to Conceptualism, and consequently, as 
an approach to Berkeley's position. Nevertheless, 
Grimm's statement, 1 that Hume's theory of Nominal- 
ism misrepresents Berkeley's, does not seem to be 
open to criticism. The fact that the "distinction 
of reason" is not drawn in the Inquiry cannot be 
regarded as having any special significance, since in 
the later work, not only is the treatment of general 
ideas almost entirely omitted, but this omission is 
easily explained. In the Treatise, Hume gave an 
exhaustive discussion of his doctrine because, (1) he 
regarded it as ' ' one of the greatest and most valuable 
discoveries" that had been made "of late years in 
the republic of letters"; and (2) he endeavored to 
confirm it by arguments which he hoped would "put 
it beyond all doubt and controversy." 2 In the In- 
quiry, he apparently assumed that he had succeeded 
in his object, 3 and consequently, thought it unneces- 
sary to discuss the question again, particularly within 
the limits of a popular essay. 

§ 14. Conclusion.— The main conclusions of the 
chapter may now be briefly stated : 

1. In the treatment of the laws of association the 
position of both works is essentially identical. In 
the Treatise, Hume discovers inductively that there 
are three general principles of association, and he 
suggests a physiological explanation of them. In the 
Inquiry, he discovers in like manner that there are 

1 Zur Gesch. d. Erkenntnisprollems, p. 461. 

2 P. 325. 3 p. 12 7. 



ASSOCIATION AND COMPLEX IDEAS. 87 

the same three general laws; but instead of attempt- 
ing to explain their cause, he gives a popular treat- 
ment of their effects as illustrated in literature. In 
the earlier work, Hume remarked that nothing was 
more requisite for "a true philosopher," than to re- 
strain the intemperate desire of searching into causes ; 
and in the later, he hoped to open up a field of specu- 
lation that would be "entertaining" and "instruc- 
tive." The change of treatment, therefore, was evi- 
dently due to his desire to popularize his doctrine. 
The omission of a physiological explanation of asso- 
ciation, in the Inquiry, is in keeping with his method 
of treating perceptions. In the briefer work, he 
does not offer any physiological explanation of the. 
cause of perceptions, but implies the same view as in 
the Treatise. A similar conclusion may be inferred 
with regard to the cause of association. 

2. The products of the laws of association are com- 
plex ideas,— relations, modes, and substances. This 
classification is omitted in the Inquiry, and in its 
stead is substituted the simple division of the objects 
of reasoning into relations of ideas and matters of 
fact. Incidentally, the same view of general ideas 
is expressed as was presented at considerable length 
in the Treatise. 

The controversy on the doctrine of general ideas 
has been practically settled by experimental psychol- 
ogy. The general idea as a psychical process, or 
piece of mind, is of course particular in its existence. 
As such, however, it need not correspond to any 
particular individual thing that is included in the 
class which it represents, nor in fact to any one thing 
that exists anywhere. The error in Hume's doctrine 



88 hume's treatise and inquiry. 

lay, not in his reasoning, but in his assumed data. He 
did not remain sufficiently true to his experimental 
method. The visualizing imagination with which he 
was endowed produced a psychological mirage, from 
the subtle illusions of which he never succeeded in 
completely freeing himself. He failed to discover: 
(1) that some minds think mainly in images, others 
in symbols; and (2) that the same mind may think 
in images, or in symbols, according as the subject- 
matter of thought is uncommon, or familiar. A pupil, 
for example, when beginning the study of algebra has 
a constant tendency to give some definite content to 
the characters employed in the reasoning; but on be- 
coming conversant with algebraic processes, he makes 
the symbols alone serve as the vehicle of thought. 
The general idea may vary from a definite mental 
image to a mere symbol. Croom Robertson struck 
the nail on the head when he remarked i 1 ' ' There are 
concepts which there is no possibility of definitely 
representing and which the mind keeps hold of only by 
the help of a definite name or sign. On the other hand, 
there is a kind of image, more or less definite, which in 
certain circumstances arises in the mind as representa- 
tive of a number of resembling objects without being 
exactly representative of any of them, and which is 
thus a true concept." In every concept, the impor- 
tant factor for knowledge is not the psychological proc- 
ess, but the logical, the element of meaning. With 
this truth, indeed, Hume does not seem to have been 
wholly unacquainted, as is seen in his brief discussion 
on the "distinction of reason." But its full force, 
or true significance, he completely failed to perceive, 
i Mind, Vol. IV, p. 553. 



CHAPTER V. 

SPACE AND TIME. 

§ 15. Infinite Divisibility. — P 'ar.t II of the Treatise 
contains Hume's doctrine of space and time. In this 
discussion dialectic skill and profound originality are 
everywhere manifest. But the author's intellectual 
power is not organized. His visualizing imagination 
and erroneous presuppositions color and distort the 
argument to such an extent that this discussion, not- 
withstanding the exceedingly great merits of the ex- 
position, is the most obscure, intricate, vacillating, 
and even self-contradictory in all his philosophical 
writings. Hume indeed seems to have been somewhat 
conscious of the difficulties inherent in this part of 
his system, for he entered upon his task with unusual 
care and forethought. In the last section of Part 
I he dealt with general ideas, thus preparing the way 
for the treatment of space and time in Part II. And 
here, before grappling with his subject proper, he dis- 
posed of the minor questions concerning the infinite 
divisibility of ideas, and the infinite divisibility of 
space and time. 

Ideas, according to Hume, are not infinitely divis- 
ible, because : (1) "the capacity of the mind is limited, 
and can never attain a full and adequate conception 
of infinity"; and (2) "whatever is capable of being 
divided in infinitum, must consist of an infinite num- 
ber of parts." Hence it follows, "that the idea, 
which we form of any finite quality, is not infinitely 

89 



90 hume's treatise and inquiry. 

divisible, but that by proper distinctions and separa- 
tions we may run up this idea to inferior ones, which 
will be perfectly simple and indivisible. ' ,1 

It is not quite clear, however, what the nature or 
characteristics of these indivisible ideas are. For 
Hume further asserts: 2 "When you tell me of the 
thousandth and ten thousandth part of a grain of 
sand I have a distinct idea of these numbers and of 
their different proportions; but the images, which I 
form in my mind to represent the things themselves, 
are nothing different from each other, nor inferior to 
that image, by which I represent the grain of sand 
itself, which is supposed so vastly to exceed them. 
What consists of parts is distinguishable into them, 
and what is distinguishable is separable. But what- 
ever we may imagine of the thing, the idea of a grain 
of sand is not distinguishable, nor separable into 
twenty, much less into a thousand, ten thousand, or an 
infinite number of different ideas." Yet on the fol- 
lowing page, he remarks: "This however is certain, 
that we can form ideas, which will be no greater than 
the smallest atom of the animal spirits of an insect a 
thousand times less than a mite." Hume's position 
seems to be this : one can form an idea about anything 
whatever that can be presented in imagination, no 
matter how small it may be ; but this idea itself, if of 
a very minute object, can be divided at most only a 
few times. 

Having shown that ideas are not infinitely divisible, 
Hume next endeavors to prove that space and time 
are not infinitely divisible. This is an easy task on 
the two assumptions which he makes: (1) "Whatever 

ip. 334. 2 P. 335. 



SPACE AND TIME. 91 

ideas are adequate representations of objects, the re- 
lations ... of the ideas are all applicable to the 
objects"; and (2) "our ideas are adequate representa- 
tions of the most minute parts of extension." 1 There- 
fore, since ideas are not infinitely divisible, space or 
extension is not infinitely divisible. The reasoning 
concerning the infinite divisibility of space holds also 
with respect to that of time. 2 The author is now 
ready to give his derivation of the ideas of space and 
time. The two subjects may be treated separately. 

§ 16. Space.— Hume's doctrine of space and time 
is very easily misunderstood. Misconception, indeed, 
rather than interpretation, has been its common lot. 
A few quotations from expounders will serve as an 
introduction to the discussion; for the diversity of 
view among Hume's critics has much justification in 
the indefinite character of his treatement. Kuhne 
asserts: 3 "Hume held, with the dogmatic metaphys- 
icians and most empiricists, space and time to be 
properties of things." Speckmann, 4 "Hume starting 
from empiricism, in his investigations concerning 
space and time, comes to a similar result as does Kant 
through his transcendental idealism. Space and 
time are also for him, in essence, nothing more than 
subjective forms of intuition of the sensibility." 
Ritter, 5 "Kant based his standpoint [in mathematics] 
on a doctrine of space different from that of Locke 
and Hume." Brede, "Extension consists, . . . 

iP. 336. 2 p. 338. 

3 Ueber das Verhaltniss d. Hume'schen u. Kantischen Er- 
kenntnisstheorie, p. 31. 

4 Ueber H. metaphysische Skepsis, p. 20. 
5 Kant u. Hume, p. 10. 

6 Der Untcrschied d. Lehrcn H., pp. 22, 23. 



92 hume's treatise and inquiry. 

according to Hume, of a finite number of visible and 
tangible mathematical points, i. e., of points which 
have no extension in themselves, . . . but which, 
when two of them come together, do not penetrate, 
but constitute a compound body consisting of parts. ' ' 
Seth, 1 "Time and space are, by [Hume's] own show- 
ing, two different manners in which perceptions are 
disposed, and in virtue of which they necessarily lose 
their character of isolated particulars. . . . They 
are relations." 

In accordance with his habitual lack of precision, 
Hume uses space and extension synonymously, also 
object and impression. 2 He gives the following ac- 
count of the derivation of the idea of space: "Upon 
opening my eyes, and turning them to the surround- 
ing objects, I perceive many visible bodies ; and upon 
shutting them again, and considering the distance 
betwixt these bodies, I acquire the idea of extension. ' ' 3 
Thus he regards space or extension as a quality of 
visible bodies, that is, a quality of impressions; and 
he seems to hold that the idea of extension is distance, 
or a copy of distance. But distance is a relation, as 
he himself explained formerly, "because we acquire 
an idea of it by the comparing of objects." 4 Hence, 
true to his philosophical principles, he immediately 
adds: "My senses convey to me only the impressions 
of colored points, disposed in a certain manner. If 
the eye is sensible of any thing farther, I desire it 
may be pointed out to me. But if it be impossible 
to shew any thing farther, we may conclude with 
certainty, that the idea of extension is nothing but 

« Scottish Phil., p. 56. 2 Qf. pp. 341, 345. 

3 P. 340. * P. 322. 



SPACE AND TIME. 93 

a copy of these colored points, and of the manner of 
their appearance." 1 Here Hume encounters a diffi- 
culty. He might have said that the idea of space is 
distance, or a copy of distance. But now, since he 
states that the senses convey only the impression of 
colored points disposed in a certain manner, it fol- 
lows that the idea of space is a copy of color and its 
manner of appearance. In short, space or extension 
is a "compound impression" consisting of "several 
lesser impressions, that are indivisible to the eye or 
feeling, and may be called impressions of atoms or 
corpuscles endowed with color and solidity." 2 And 
the idea of space, being but a copy of extension, "con- 
sists of parts" that are indivisible, and is itself ex- 
tended. 3 "The idea of space or extension is nothing 
but the idea of visible or tangible points distributed 
in a certain order." 4 

Thus far, Hume has given an account of the de- 
rivation of only the particular idea of space. He 
next explains the process of transition to the general 
idea. "When we have had experience of the different 
colors, and have found "a resemblance in the dis- 
position of colored points, of which they are composed, 
we omit the peculiarities of color, as far as possible, 
and found an abstract idea merely on that disposi- 
tion of points, or manner of appearance, in which they 
agree. Nay even when the resemblance is carried 
beyond the objects of one sense, and the impressions 
of touch are found to be similar to those of sight in 
the disposition of their, parts; this does not hinder 
Hie abstract idea from representing both, upon ac- 

1 P. 341. 2 cf. pp. 345, 34G, 3GG. 

3 C'/\ pp. 344, 523, 527. *P. 358. 



94 hume's treatise and inquiry. 

count of their resemblance." 1 The general idea of 
space, therefore, is the "disposition" of visual or 
tangible points, or "the manner" of appearance in 
which they agree; or as elsewhere put, the general 
idea of space is "no separate or, distinct" idea, but 
merely that of "the manner or order" in which ob- 
jects exist. 2 

But the author of the Treatise does not satisfy him- 
self with a mere exposition of his theory of space. 
After presenting his doctrine, he proceeds to answer 
some objections that may be urged against it, and at 
the same time to define it more exactly. Since space 
is not infinitely divisible, what is the nature, one may 
ask, of its ultimate indivisible elements? Hume re- 
jects both the theory of mathematical points, and that 
of physical points. Each of these views is absurd. 3 
He adopts an intermediate position, and regards the 
ultimate indivisible elements of space as mathematical 
points endowed with color or solidity. 4 This, how- 
ever, is equivalent to saying that they are physical 
points. The author even admits, although implicitly, 
that they are such, when he asserts : 5 ' ' That compound 
impression, which represents extension, consists of sev- 
eral lesser impressions, that are indivisible to the eye 
or feeling, and may be called impressions of atoms or 
corpuscles endowed with color and solidity." An- 
other essential part of Hume's doctrine is that the 
idea of space necessarily implies the existence of 
matter. The idea of pure space, or of a vacuum is 
impossible for "the idea of space or extension is 
nothing but the idea of visible or tangible points dis- 
tributed in a certain order." 6 

J P. 341. 2 p. 34 6# *IU&. 

* Cf. pp. 346, 347. s P. 345. « P. 358. 



SPACE AND TIME. 95 

§ 17. Time.— The exposition of time is similar to 
that of space. The idea of time is derived from "the 
succession of our perceptions of every kind, ideas as 
well as impressions, and impressions of reflection as 
well as of sensation. ' n And the abstract idea of time 
"is not derived from a particular, impression mixed 
up with others, and plainly distinguishable from 
them ; but arises altogether from the manner, in which 
impressions appear to the mind, without making one 
of the number.' ' 2 Consequently, the particular idea 
of time "can plainly be nothing but different ideas, 
or impressions, or objects disposed in a certain man- 
ner, that is, succeeding each other ' ' ; 3 and the general 
idea of time is "no separate or distinct" idea, but 
merely that of "the manner or order" in which ob- 
jects exist, 4 Yet, since it is impossible to have an idea 
of pure or empty time, the general idea of time is 
always represented "in the fancy by some individual 
idea of a determinate quantity and quality." 5 

§ 18. Treatment of Space and Time in the Inquiry. 
—In the Inquiry, there is nothing corresponding to 
Part II of the Treatise ; hence, the discussion of space 
and time is here omitted. Yet, in the twelfth section 
and appended notes, there are some statements which 
imply that practically the same view of space and 
time prevails in both works. 6 Space and time are not 
infinitely divisible. 7 The ideas of space and time are 
derived from objects of sight and touch, by means of 
the senses. 8 And it is impossible to form an idea of 
empty space, or of empty time. 9 

iP. 341. 2 p. 343. 3 p. 344. * P. 34G. 5 p. 342. 

6 Cf. Baumann, Die Lchren v. Raum, Zeit u. Mathematih, 
II, p. 482. 

7 Pp. 128, 129. s pp. 120, 127. * P. 127. 



96 hume's treatise and inquiry. 

There is one remark, however, in the Inquiry, which 
is inconsistent, formally at least, with a statement in 
the Treatise, and which accordingly calls for brief 
comment. In a foot-note Hume observes: 1 "What- 
ever disputes there may be about mathematical points, 
we may allow that there are physical points ; that is, 
parts of extension, which cannot be divided or less- 
ened, either by the eye or imagination. ' ' It has al- 
ready been pointed out that, in the Treatise, he re- 
jected the theory of physical points as an absurdity. 
It was inconsistent with his general maxim, "what- 
ever objects are different are distinguishable." For 
"a real extension, such as a physical point is supposed 
to be, can never exist without parts, different from 
each other." 2 Yet it has also been shown that, al- 
though he rejected the doctrine of physical points in 
theory, he adopted it in practice. Consequently, the 
avowal here of the system of physical points is not of 
much significance. 3 It is interesting to note that, in 
the appendix, Hume had almost arrived at the same 
view. "If it be asked," he says, 4 "if the invisible 
and intangible distance, interposed betwixt two ob- 
jects, be something or nothing: 'it is easy to answer, 
that it is something, viz., a property of the objects, 
which affect the senses after such a particular, man- 
ner.' " This statement, it is true, is not quite cor- 
rect. For an invisible, intangible distance cannot af- 
fect the senses in any manner whatever. But the im- 
portant circumstance to notice is, that what Hume 

1 P. 128. 2 1, p. 346. 

*Cf. Meyer, Hume u. Berkeley's Phil. d. Math., p. 21, and 
n. 3; Brede, Der Unterschied d. Lehren H., p. 46. 
* 1, p. 368. 



SPACE AND TIME. 97 

calls an invisible, intangible distance lie really regards 
as a property of objects. 

Space and time were extremely difficult subjects 
for the author of the philosophy of human nature to 
deal with, on account of the falsity of some of his 
presuppositions. It is not surprising, therefore, that 
Part II is the most unsatisfactory division of the 
Treatise, and that it was omitted in the Inquiry. It 
is evident, however, that Hume regarded this part of 
his work as being of considerable importance, since 
he rewrote it— at least the treatment of space,— as is 
indicated by a letter to Millar in 1755. But although 
he sent the essay—-" The Metaphysical Principles of 
Geometry"— to his publisher, he withdrew it before 
it was printed, because in the meantime Lord Stan- 
hope, one of the most eminent mathematicians of his 
day, convinced him that "either there was some defect 
in the argument, or in its perspicuity." 1 This is the 
only reason positively known why Part II of the 
Treatise, although rewritten, was never published in 
its later form. 

Before this letter to Millar became generally known, 
writers on Hume assigned many reasons to explain 
why Part II of the Treatise was omitted in the In- 
quiry. The argument of Brede is one of the most 
plausible, and is in substance as follows: 2 "As in the 
Treatise, Hume also assumes in the Essay indivisible, 
but real, visible and tangible points as the parts of 
extension. These are distinguished from the mathe- 
matical points of the Treatise only through their name, 
physical points. On a closer investigation of this 

i Hill, Letters of D. H., p. 230. 

2 Dcr TJntcrschied d. Lehren H., p. 46. 

7 



98 hume's treatise and inquiry. 

subject Hume does not enter. Such would have been 
impossible, without a direct criticism of his former 
view, according to which physical points could be 
distinguished into different parts. And then he would 
have been involved in great difficulties, in the appli- 
cation of his axiom, that whatever is distinguishable 
is separable.' ' It is possible that a desire to avoid 
this contradiction may have had some influence on 
Hume when writing the later work. But as Brede 
himself observes, "the physical points" of the In- 
quiry are different only in name from "the mathe- 
matical points" of the Treatise. It is scarcely likely, 
therefore, that in the application of his maxim, Hume 
would have found himself involved in any greater 
difficulties in the one case than in the other. Rather, 
the cause of the omission of Part II is general, not 
special. The subject is an abstract one; and Hume's 
ideas on space and time were neither perfectly clear, 
nor strictly accurate. 

§ 19. Conclusion.— It is easy, of course, as Green 
has abundantly shown, to discover inconsistencies in 
Hume's statement of his doctrine of space and time. 
For instance, space or extension is "nothing but a 
composition of visible or tangible points disposed in 
a certain order." 1 Upon shutting one's eyes and con- 
sidering "the distance" between bodies, one acquires 
"the idea of extension." 2 Yet, "every idea is de- 
rived from some impression, which is exactly similar 
to it." 3 Or again, the particular idea of space is 
"nothing but a copy of . . . colored points, and of 
the manner of their appearance." 4 The general idea 
of space is "no separate or distinct" idea, "but 
*P. 366. 2 p. 340. *IUd. * P. 341. 



SPACE AND TIME. 99 

merely" that of "the manner or order., in which ob- 
jects exist." 1 Yet, all general ideas "are really noth- 
ing but particular ones, considered in a certain 
light." 2 But what the critics have failed to notice 
is, that Hume came remarkably near giving a valid 
and satisfactory exposition of space and time. True, 
they have admired the exceedingly ingenious manner 
in which he presented his argument. Thus if asked, 
what is space? he replies, "the manner or order in 
which objects exist." If asked, whence is the idea of 
space derived? he replies, "from objects of sight or. 
touch ? ' ' And if asked, what is the idea of space ? he 
replies, "a copy" of visual or tangible points, or "the 
disposition" of visual or tangible points, according as 
the one answer, or the other, suits his purpose; the 
former answer having reference to the particular idea 
of space derived logically in accordance with his sys- 
tem, and the latter having reference to the general 
idea of space as it prevails in popular thought. The 
critics, however, have been so busily engaged in de- 
tecting fallacies, and so intent on observing inconsis- 
tencies, that they have almost entirely overlooked the 
really significant points in his doctrine. 

Hume's exposition of space and time has much 
more than plausibility to commend it. For the sake 
of brevity the discussion will be limited to the subject 
of space, as the argument, with but slight modifica- 
tions, holds equally with regard to that of time. It is 
one of the chief distinguishing traits of the philos- 
opher of Ninewells that he was the interpreter of 
actual experience, and not a prophet, nor a seer. 
That extension is an attribute of visual and tactual 

! P. 34G. 2 p. 341. 

L ofC. 



100 hume's treatise and inquiry. 

sensations is now a common-place in psychology. 
Such also was the view of Hume; but in his termi- 
nology sensations are called impressions. 1 It is true, 
"Ward, James, and a few other psychologists maintain 
that space is an attribute of all sensations. Whether 
or not this is the case depends entirely upon the 
definition of the term. Certain it is that extension 
is an object of sight and touch, that space is an as- 
pect of the real world of things. And not only was 
Hume right in holding that space is a datum of sen- 
suous experience, but he was also right in indicating 
that there is a fundamental difference between the 
individual perception of space, and the general notion. 
In this respect, he had a truer vision than had Im- 
manuel Kant. His intellectual eye was not dimmed 
by the mists of German rationalism, nor was his 
natural force abated by wrestling with noumenal ex- 
istences. Although in this instance, however, the 
open minded Scotsman had the truer psychological 
insight, it must be admitted that his visualizing im- 
agination and erroneous conception of general ideas 
misled him with regard to the exact nature of the 
difference between the particular perception of space, 
and the general notion. The essential feature of the 
latter is not the psychological element, but the epis- 
temological ; and this the author of the philosophy of 
human nature failed to perceive. For a similar rea- 
son also Hume's treatment of infinite divisibility is 
palpably defective. The particular idea of space, as 
he rightly maintained, is not capable of division to 
infinity; but the general idea of space, the funda- 
mental characteristic of which is the element of mean- 
» P. 341. 



SPACE AND TIME. 101 

ing, is "without question infinitely divisible. Of like 
nature, moreover, is Hume's treatment of a vacuum. 
He was certainly right in insisting that pure or empty 
space is never an object of perception. For what is 
ordinarily called the perception of space, the partic- 
ular idea of space, is really the perception of diffuse 
matter., bounded to a greater or less extent by objects 
of a denser quality. 1 On the other, hand, however, 
he was mistaken when he asserted that the idea of 
pure space, or of a vacuum is impossible. For by 
means of abstraction one may have a general idea of 
space, an idea of pure or empty space, as the possi- 
bility of movement-sensations, or as the system of 
space relations— actual or possible— which obtains 
among external things. 2 

1 Cf. Russell, Foundations of Geometry, pp. 194/ 196. 
*Cf. Fullerton, Phil. Rev., Vol. X, p. 599; Nichols, The 
Psychology of Time, pp. 113, 139. 



CHAPTER VI. 

KNOWLEDGE— INTUITIVE AND DEMONSTRATIVE. 

§ 20. The Faculties of Mind.— The accounts of 
Hume's theory of knowledge, as presented in both 
the Treatise and Inquiry, are exceedingly perplexing. 
This is due, in large measure, to the fact that the 
epistemological terminology of his day was not ade- 
quate to the treatment of his subject-matter. At one 
time he did not properly define his terms ; at another, 
he did not consistently hold to his definitions. More- 
over, not having a sufficient number of appropriate 
terms at his command, he occasionally gave to the 
same wor.d different, or provisional definitions, ac- 
cording as the circumstances of the case required, 
without explaining the relation of these definitions 
to one another. This is particularly true of the names 
denoting mental faculties, or sources of knowledge. 
By faculty he meant, in general, the mind acting in a 
certain way. Of those which he recognized, the more 
important are the six following: sensation, memory, 
imagination, understanding or reason, reflection, and 
instinct. 

Sensation, immediately or mediately, is the source 
of all knowledge. When impressions of sense return 
as ideas, they are called memory, or imagination, ac- 
cording as they possess— as a general rule,— or do not 
possess, a certain degree of force and vivacity, and a 
certain measure of fixity of order,. When the ideas 
of imagination— or of memory— lose, to a certain ex- 

102 



KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 103 

tent, their sense content, and are combined in new 
forms by means of comparison, abstraction, or gen- 
eralization, they become transformed into conceptions, 
and are attributed to the understanding or. reason. 
Thus imagination and reason, like imagination and 
memory, differ only in degree. As Hume said, 1 the 
understanding or reason is but "the general or. more 
established properties of the imagination. ' ' Hence, 
memory, imagination, and reason are different stages 
of one and the same process. 2 Reflection sometimes 
accompanies, sometimes follows sensation, memory, 
imagination, and reason. It is in part the basis of 
instinct. 

Instinct is an indispensable factor in the philosophy 
of human nature. Of amorphous character, it plays 
many parts. It corresponds somewhat with the ele- 
ment of feeling in perceptions; it is a sentiment, or 
manner of conception. It is also closely related to 
sensation. "It seems evident/' says Hume, 3 "that 
men are carried, by a natural instinct or preposses- 
sion, to repose faith in their senses." Moreover, in- 
stinct includes, to a greater or less extent, imagination, 
belief, habit, custom, and experiential or moral rea- 
soning. "All belief of matter, of fact or real exist- 
ence/ ' Hume affirms, in the Inquiry, 4 "is derived 
merely from some object, present to the memory or 
senses, and a customary conjunction between that and 
some other object. . . . This belief is the necessary 

il, p. 547; cf. IV, p. 38 n. 

2 Cf. Gore, The Imagination in Spinoza and Hume, p. 74. — 
" Reason is the imagination generalized, and the imagination 
is reason particularized." 

3 IV, p. 124; cf. I, pp. 483, 548. 

4 P. 40; cf. I, pp. 403, 474, 475. 



104 hume's treatise and inquiry. 

result of placing the mind in such circumstances. It 
is an operation of the soul, when we are so situated, 
as unavoidable as to feel the passion of love, when we 
receive benefits: or hatred, when we meet with in- 
juries. All these operations are a species of natural 
instincts, which no reasoning or process of the thought 
and understanding is able, either to produce, or to 
prevent." Again, 1 "Nothing leads to this inference 
[based on the idea of cause and effect] but custom or 
a certain instinct of our nature. ' ' And in the Treatise 
he asserts: 2 "Reason [experiential reasoning] is noth- 
ing but a wonderful and unintelligible instinct in our. 
souls, which carries us along a certain train of ideas, 
and endows them with particular qualities, according 
to their particular situations and relations. . . . 
Nature may certainly produce whatever can arise 
from habit : Nay, habit is nothing but one of the prin- 
ciples of nature, and derives all its force from that 
origin. ' ' Furthermore, instinct is a species of knowl- 
edge derived from "the original hand of nature," and 
which is capable of little or no advancement. 3 Finally, 
it may be regarded as including what are commonly 
called the ideals of reason,— goodness, beauty, tr.uth, 
duty, etc. i ' There is a great difference, ' ' says Hume, 4 
"betwixt such opinions as we form after a calm and 
profound reflection, and such as we embrace by a kind 
of instinct or natural impulse, on account of their 
suitableness and conformity to the mind. ' ? Naturally, 
therefore, instinct is superior to reason. It is the 
great guide of human life. 

iR 131. 2 p. 471- C f t pp. 387, 404. 

3 IV, p. 88; cf. I, pp. 470, 471. 

*I, p. 501; cf. pp. 474, 475, 478, 548, 549. 






KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 105 

For the sake of clearness, it is well to note that, in 
the Inquiry, Hume made less use of imagination, and 
more use of instinct, than he did in the Treatise. 
Many mental processes which, in the earlier work, 
were attributed to imagination are, in the later, as- 
cribed to instinct, custom, or nature. This change of 
treatment, although it does not indicate any change 
of doctrine, seems to imply a truer appreciation of the 
function of instinct. Yet it does not necessarily 
imply even this much. At most, it only rendered 
explicit in the Inquiry, what was implicit in the 
Treatise. For instinct, custom, or habit is always the 
basis or ground of the transition of imagination. The 
full significance of the change it is probably impos- 
sible to determine; for Hume used instinct, custom, 
habit, and imagination more or less interchangeably 
in both works. In the Treatise he asserted i 1 ' ' When 
I consider the influence of this constant conjunction, 
I perceive, that such a relation can never be an object 
of reasoning, and can never operate upon the mind, 
but by means of custom, which determines the imag- 
ination to make a transition from the idea of one 
object to that of its usual attendant, and from the 
impression of one to a more lively idea of the other. ' ' 
Again, 2 "Reason [experiential reasoning] is nothing 
but a wonderful and unintelligible instinct in our 
souls, which carries us along a certain train of ideas, 
and endows them with particular qualities, according 
to their particular situations and relations. ' ' That is, 
reasoning is regarded equally as a transition of the 
imagination, and as a wonderful and unintelligible 
instinct. Likewise, in the Inquiry, the author stated: 3 

iP. 4G4; cf. p. 487. * P. 471. 3 p. G 2; of. p. 05. 



106 hume's treatise and inquiry. 

" After a repetition of similar instances, the mind is 
carried by habit, upon the appearance of one event, 
to expect its usual attendant, and to believe that it 
will exist. This connection, therefore, which we feel 
in the mind, this customary transition of the imagina- 
tion from one object to its usual attendant, is the sen- 
timent or impression from which we form the idea of 
power or necessary connection." Further, 1 ""We 
have no argument to convince us, that objects, which 
have, in our experience, been frequently conjoined, 
will likewise, in other instances, be conjoined in the 
same manner; and . . . nothing leads us to this 
inference but custom or a certain instinct of our 
nature." " Provided we agree about the thing," 
Hume once said, "it is needless to dispute about the 
terms. ' ' Accordingly, in the briefer wort, instead of 
attributing certain mental processes directly to imag- 
ination, as formerly, and then indirectly to custom or 
instinct, he often ascribed them to custom, instinct, or 
nature directly. 

§ 21. Intuitive Knowledge. — In the philosophy of 
human nature, impressions and ideas are the ultimate 
elements of knowledge. These possess certain qualities 
which constitute the ground of the three natural rela- 
tions. Natural relations are the source of the seven 
kinds of philosophical relations, also of modes and 
substances. And the philosophical relations are the 
basis of the different degrees of certainty. In Part 
III of the Tr.eatise, Hume deals with this last problem 
under the title "Knowledge and Probability." As 
has already been stated, 2 he distinguishes two classes 
of philosophical relations : those that depend entirely 

ip. 130; cf. p. 40. 2 p. 83. 






KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 107 

upon the ideas compared, and those that may be 
changed without any change in the ideas. The 
former class-relations of resemblance, contrariety, 
degrees of quality, and proportions in number and 
quantity— constitute "the foundation of science/' and 
are objects of knowledge and certainty. The latter- 
identity, contiguity, and causation,— are the ground 
of probability. 1 Knowledge is of two kinds, intuitive, 
and demonstrative; and probability also is of two 
kinds, proofs, and probability in a narrower sense. 2 
Proofs and probability will be treated in the three 
following chapters. 

Intuitive knowledge means sense and memory 
knowledge. It is based on the relations of resem- 
blance, contrariety, and degrees of quality. It arises 
immediately from the observation, or comparison of 
impressions and ideas. It does not necessarily mean 
exact, nor certain knowledge, but only that kind of 
knowledge which the mind obtains ' ' at first sight, ' ' or 
which it arrives at immediately on the perception, 
among impressions and ideas, of the relations of re- 
semblance, contrariety, or degrees of quality. Thus, 
in the Treatise, Hume asserts: 3 "And though it be 
impossible to judge exactly of the degrees of any 
quality, such as color, taste, heat, cold, when the dif- 
ference betwixt them is very small; yet it is easy to 
decide, that any of them is superior or inferior to 
another, when their difference is considerable. And 
this decision we always pronounce at first sight, with- 
out any inquiry or reasoning." 

There is no specific treatment of intuitive knowl- 
edge in the later work. In the earlier, Hume, follow- 

1 Pp. 372, 373. 2 p. 423. »P, 373. 



108 hume's treatise and inquiry. 

ing Locke, regarded knowledge as the perception of 
the agreement or disagreement of impressions and 
ideas; consequently, he considered the philosophical 
relations as the ground or possibility of reasoning. 
But in the Inquiry, he omitted the table of philosoph- 
ical relations, and for the classification of knowledge, 
or complex ideas, into relations, modes, and sub- 
stances, he substituted the twofold division of "all 
the objects of human reason or inquiry," viz., rela- 
tions of ideas, and matters of fact ;* relations of ideas 
corresponding to those philosophical relations that 
depend entirely upon the ideas compared, and matters 
of fact corresponding, in large measure, to those phi- 
losophical relations that may change while the ideas 
compared remain the same. Accordingly, under the 
former division he includes the sciences of arithmetic, 
algebra, and geometry, and in short, every affirmation 
which is either "intuitively or demonstratively cer- 
tain, ' ' and under the latter, the natural and historical 
sciences of probability. 2 In Book III of the Treatise 
of Human Nature* Hume reasserted the position of 
Book I, that resemblance, contrariety, degrees of 
quality, and proportions in number and quantity are 
the only relations which are "susceptible of certainty 
and demonstration. ' ' Although in the Inquiry 4 he 
thought that "the sciences of quantity and number" 
might be pronounced "the only proper objects of 
knowledge and demonstration," there is no reason to 
suppose that his view of intuitive knowledge was dif- 
ferent from that presented in the Treatise. He im- 
plies the same distinction as formerly between intui- 

1 P. 20. 2 pp. 20, 22, 135. 

all, pp. 240, 241. *P. 134. 



KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 109 

tive and demonstrative knowledge, when he says that 
"the connection" between propositions is not "intui- 
tive," if it "requires a medium." 1 

It may be imagined, perhaps, that there is some 
special significance in the substitution, in the later, 
work, of the twofold division of knowledge— relations 
of ideas, and matters of fact— for the threefold divi- 
sion of the products of the laws of association, and 
for the subdivision of philosophical relations. Such, 
however, does not seem to be the case. Hume wrote 
the Treatise with Locke often in mind. But although 
he followed his master in some reduplications, cross- 
divisions, and contradictions, he endeavored to im- 
prove upon Locke's celebrated Essay. Ideas of sensa- 
tion and reflection, as the original elements of knowl- 
edge, he transformed into impressions and ideas of 
sensation and reflection. While he accepted Locke's 
definition of knowledge, and his classification of com- 
plex ideas ; instead of the four kinds of agreement and 
disagreement between ideas, as the necessary condition 
of knowledge, he put forward the seven kinds of phi- 
losophical relations. The two tables are related as 
follows : 

1. Identity and diversity. 1, 2, 3. Identity, resemblance, and 

contrariety. 

2. Relation. 4, 5, 6. Contiguity or relations of 

time and place, degrees 
of quality, and propor- 
tions in number and 
quantity. 

3. Co-existence. 7. Cause and effect. 

4. Real-existence. 

It will be observed that Hume's classification of 
i P. 30. 



110 hume's treatise and inquiry. 

philosophical relations differs considerably from 
Locke's four kinds of agreement or disagreement 
between ideas; for not only has the author of the 
Treatise naturally no place for knowledge of sub- 
stance or real-existence, but his relations of identity 
and contrariety have not the same meaning as Locke 's 
agreement or disagreement in the way of identity 
and diversity. 

As Hume developed his system of philosophy, he 
worked gradually farther away from Locke's theory 
of knowledge, and approached, in certain respects, 
the position of Butler. 1 Soon he adopted relations 
of ideas and matters of fact as a convenient classifica- 
tion of the objects of knowledge. It is one of Pat- 
ten's 2 many misconceptions that this classification 
first appeared in the Inquiry. On the contrary, it 
developed step by step with the natural progress of 
the author's thought, as he proceeded from the con- 
sideration of theoretical philosophy to that of prac- 
tical. In some passages of the Treatise, for example, 
it is hinted at, or implied. 3 In Book II of the Treatise 
of Human Nature it is, for the first time, explicitly 
stated. ' ' Truth is of two kinds, ' ' says Hume, 4 ' ' con- 
sisting either in the discovery of the proportions of 
ideas, considered as such, or in the conformity of our 
ideas of objects to their real existence." And in 
Book III of the Treatise of Human Nature it is fre- 
quently employed, as in the following passage: 5 "As 
the operations of human understanding divide them- 

1 Cf. Analogy, p. 3. 

2 The Development of English Thought, p. 225. 
s Cf. pp. 394, 395, 483. 

< II, p. 223; cf. p. 227. 

511, p. 240; cf. p. 236. , , , > ; * 



INTUITIVE AND DEMONSTRATIVE. Ill 

selves into two kinds, the comparing of ideas, and the 
inferring of matter of fact; were virtue discovered 
by the understanding ; it must be an object of one of 
these operations, nor is there any third operation of 
the understanding, which can discover it." The im- 
possibility of giving a popular exposition of philo- 
sophical relations, or a satisfactory treatment within 
a limited compass was probably the chief cause for 
the introduction in their stead, in the Inquiry, of the 
simple division of objects of knowledge into relations 
of ideas and matters of fact. 1 

§ 22. Demonstrative Knowledge.— Demonstrative 
knowledge is that which arises from the understand- 
ing or reason. It is based on the relations of num- 
ber and quantity. Very simple relations of number 
or quantity, such as may be observed at ' c one view, ' ' 
are more properly intuitive knowledge. But when 
these relations can be perceived only by means of "a 
chain of reasoning," they constitute demonstrative 
knowledge. 2 The sciences of demonstration are arith- 
metic, algebra, and geometry. 

Hume's doctrine of mathematics has always been 
one of the interesting puzzles in his philosophy. It 
has been a subject of universal contention, and many 
expositions— as well as criticisms— of it have been 
given. These, however, at most have been but par- 
tially correct, and have resulted rather in contradic- 
tion and confusion, than in conviction or illumination. 
A few quotations, while exhibiting the variety of in- 
terpretation on the question, may suggest some guid- 
ing thoughts for a new solution. Masaryk asserts: 3 

l Of. pp. 80-83, above. 2 Pp. 373, 374. 

8 D. 77. Skepsis u. d. Wahrschcinlichkeitsreclmung, p. G; cf. 
Windelband, Gesch. d. n. Phil, I, pp. 321, 327; Rosenkranz, 



112 hume's treatise and inquiry. 

"According to Hume, mathematics is an absolutely- 
certain science, because founded on a priori prin- 
ciples.' ' Watson, 1 "The mathematical doctrine of 
Hume may be stated in these three propositions: (1) 
Mathematical judgments rest upon impressions of 
sense; (2) they are singular; (3) they are only ap- 
proximately true." Spicker, 2 "We must here note 
attentively that Hume, equally with Kant, considers 
mathematics as a pure activity of thought, which 
takes place independently of all experience, and is, 
therefore, a priori certain." Stuckenberg, 3 "Mathe- 
matics, which Hume considered as a relation of ideas, 
is grounded by him also exclusively on experience." 
Petzholtz/ "Mathematics belongs to the sciences which 
treat of relations of ideas, whose propositions, there- 
fore, we discover through the pure activity of thought. 
. . . While Hume allows to arithmetic this uncon- 
ditioned certainty, he does not attribute such without 
reserve to geometry." Caird, 5 "Hume in his earlier 
treatise attempted ... to trace back the ideas of 
mathematics to impressions of space and time: but 
the attempt led him to the denial of the objective 
validity of mathematical truth, in so far as it goes 
beyond the possibility of empirical measurement." 
Gesch. d. Kantischen Phil., p. 23; Volkelt, Erfahrung u. 
Denken, p. 108; Uhl, H. Stellung in d. englischen Phil., pp. 
31, 32; Ritter, Kant u. Hume, pp. 7, 9. 

1 An Outline of Philosophy, p. 357. 

2 Kant, Hume u. Berkeley, pp. 110, 117, 125; cf. Gordy, 
Hume as Sceptic, p. 1. 

3 Grundprobleme in Hume, p. 18; cf. I, pp. 222, 223. 

4 Die Hauptpunkte D. H. Erkenntnislehre, p. 29 ; cf. Adam- 
son, Ency. Brit., art. Hume, p. 353. 

5 The Critical Philosophy of I. K. t I, p. 256; cf. Mahaffy and 
Bernard, Katit's Critical Philosophy, II, p. 23, and n. 



KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 113 

Webb, 1 "As to Hume's opinion with reference to the 
a priori character of mathematics, there can be no 
intelligent diversity of opinion. . . . He abandoned 
the doctrine of the Treatise. ' ' Riehl, 2 " It is erroneous 
to assert, that Hume has not doubted the validity of 
pure mathematics, since he, in the Treatise (and even 
in the Inquiry), not only doubts but positively im- 
pugns the evidence for geometry, and restricts validity 
to the abstract part of mathematics, the pure doctrine 
of quantity." Statements similar to these might be 
quoted indefinitely. They indicate great diversity in 
the answers given to the four, following questions: 
(1) Is mathematics, according to Hume an a priori 
science? (2) Is it an absolutely certain science? 
(3) Is it a perfectly exact science? (4) Is there any 
difference between the respective positions of the 
Treatise and Inquiry on the three preceding ques- 
tions ? These quotations also indicate that the ground 
of their diversity is not solely subjective differences 
in the writers. The solution of the problem is to be 
sought only in a study of the objective differences that 
exist in Hume 's treatment. And the key to this solu- 
tion is the discernment that Hume, in the Treatise, 
gave three different, although not distinct or separate 
accounts of mathematics, corresponding to three stages 
of development in his doctrine. These accounts may 
be called the epistemological, the logical, and the psy- 
chological. They will be treated in their order. 
I. The Epistemological Treatment of Mathematics. 

1 Veil of Isis, pp. 101, 102; cf. Long, Uebcr Hume's Lehre 
v. d. Idecn u. d. Substanz, p. 35. 

2 Der philosophische Krilicismus, I, pp. G9, 96, 97; cf. 
Windelbwnd, Hist, of Phil., p. 473; Brede, Der Untcrschied d. 
Lehrcn II., pp. 11, 35. 



114 hume's treatise and inquiry. 

—Hume's first account of his doctrine of mathematics 
is given in Parts II and III. The mathematical sci- 
ences, as already stated, are based on the philosophical 
relations of number and quantity. These relations, 
in turn, are based on certain qualities of impressions 
and ideas, 1 Geometrical relations are modes of space. 
Arithmetical and algebraic relations are modes of 
number. Both space and number are constituted of 
simple and indivisible units. The units of space 
are mathematical points, " endowed with color" or 
"solidity. " 2 But of the units of number no explana- 
tion is offered. Hume merely asserts that "the unity, 
which can exist alone, and whose existence is neces- 
sary to that of all number, . . . must be perfectly 
indivisible and incapable of being resolved into any 
lesser, unity. ' ' 3 The idea of space is derived from the 
senses of sight and touch. 4 And the idea of number 
arises from the perception of objects. 5 It is manifest, 
therefore, that all the mathematical sciences are em- 
pirical. 

Arithmetic and algebra Hume regards as perfectly / 
exact and certain sciences, because in dealing with 
numbers, the subject-matter of these sciences, "we 
are possessed of a precise standard, by which we can 
judge of [their] equality and proportion ; and accord- 
ing as they correspond or not to that standard, we 
determine their relations, without any possibility of 
error." 6 Geometry, on the other hand, he declares 
"falls short of that perfect precision and certainty, 
which are peculiar to arithmetic and algebra, . . . 
because its fundamental principles are derived merely 

1 Of. pp. 322, 323, 372. 2 Pp< 345, 347. 

3 P. 338. * Pp. 340 ; 341. 5 p p . 337^ 333. 6 p. 374. 



KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 115 

from appearances. ' n That is to say, geometry would 
be a perfectly exact and certain science, if its funda- 
mental principles, the definitions and axioms on which 
it is founded, were perfectly exact and certain. But 
these definitions and axioms are derived merely from 
the appearances of objects, and consequently, are not 
exact. Hence, the science of geometry is neither per- 
fectly exact nor certain. Yet geometry excels in ex- 
actness and certainty "the imperfect judgments of 
our senses and imagination." For although Hume 
admits that the judgments concerning geometrical 
relations are not "more exempt from doubt and error 
than those on any other subject/' 2 he maintains, at 
the same time, that the fundamental principles of 
geometry "depend on the easiest and least deceitful 
appearances," and therefore, "bestow on their con- 
sequences a degree of exactness, of which these con- 
sequences are singly incapable." 3 

Apparently inconsistent with the preceding account 
is a passage in which Hume asserts that "geometry 
fails of evidence" in one "single point"— its demon- 
strations for the infinite divisibility of extension, — 
but that ' ' all its other reasonings command our fullest 
assent and approbation." 4 This latter statement, if 
taken literally, cannot be harmonized with Hume's 
general position. But the author undoubtedly meant 
that it should be understood only in a relative sense. 
For he repeatedly affirms that geometry is not an 
exact nor certain science like arithmetic or algebra, its 
first principles having been derived from the general 
appearances of objects. 5 

1 P. 374. 2 P. 353. 3 p. 374. i P< 357. 

5 Pp. 350, 353, 354, 355. 



116 hume's treatise and inquiry. 

It may be noted, however, that if geometry dealt 
with discrete quantity, like numbers, instead of with 
continuous quantity, as is space, it would, according 
to Hume, be a perfectly exact and certain science. 1 
Arithmetic and algebra are such, because they deal 
with discrete quantity. They possess a perfect exact- 
ness and certainty, because the exact difference be- 
tween any two numbers whatever can easily be de- 
termined. The author speaks of two standards of 
certainty in geometry, one accurate, the other inac- 
curate. The inaccurate standard is the indefinite 
presentations of the senses and imagination, " derived 
from a comparison of objects, upon their general ap- 
pearance, corrected by measuring and juxta-position. ' ' 
The accurate standard is the indivisible points of 
which lines and other geometrical figures are com- 
posed. 2 But although this latter standard is theo- 
retically exact, it is impracticable both in science and 
in common life. If mathematicians be asked what 
they mean when they say that one line or surface is 
equal to, greater, or less than another, " [those] who 
defend the hypothesis of indivisible points," Hume 
asserts, 3 "need only reply, that lines or surfaces are 
equal, when the numbers of points in each are equal ; 
and that as the proportion of the numbers varies, the 
proportion of the lines and surfaces is also varied. 
But though this answer be just," he continues, "as 
well as obvious; yet I may affirm, that this standard 
of equality is entirely useless, and that it never is 
from such a comparison we determine objects to be 
equal or, unequal with respect to each other." On 
the question of the exactness and certainty of geom- 

i Pp. 351, 374. 2 pp. 35i^ 357. a P# 351 . 



KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 117 

etry, he explicitly states his position as follows: 1 "It 
appears, then, that the ideas which are most essential 
to geometry, viz., those of equality and inequality, of 
a right line and a plain surface, are far from being 
exact and determinate, according to our common 
method of conceiving them. ... As the ultimate 
standard of these figures is derived from nothing but 
the senses and imagination, it is absurd to talk of any 
perfection beyond what these faculties can judge of; 
since the true perfection of any thing consists in its 
conformity to its standard." 

The results of the discussion thus far may here be 
summarized. Proportions in number and quantity ' 
are the ground of demonstrative knowledge. But 
these proportions, like the other philosophical rela- 
tions, are derived by means of the senses. Con- 
sequently, mathematics is an empirical science. 
Arithmetic and algebra are perfectly exact and cer- 
tain sciences, since, dealing with discrete quantity, 
they possess a perfectly exact standard. But geom- 
etry, although it excels in exactness and certainty the 
inaccurate judgments of the senses or imagination, 
falls short of perfect precision, because dealing with 
continuous quantity, it lacks a perfectly exact stand- 
ard. This may be called Hume's epistemological 
treatment of mathematics. It is only one part of his 
doctrine, and is considerably modified later. 

II. The Logical Treatment of Mathematics.— In 
Part IV, the author, draws the logical consequences 
of his philosophical principles, and sums up his doc- 
trine of the understanding. In the first section he 
treats of mathematics in the following manner: 2 "In 

■ P. 35G; cf. pp. 348, 350, 353, 355. * P. 472. 



118 hume's treatise and inquiry. 

all demonstrative sciences the rules are certain and 
infallible ; but when we apply them, our fallible and 
uncertain faculties are very apt to depart from them, 
and fall into err.or. We must, therefore, in every 
reasoning form a new judgment, as a check or control 
on our first judgment or belief ; and must enlarge our 
view to comprehend a kind of history of all the in- 
stances, wherein our understanding has deceived us, 
compared with those, wherein its testimony was just 
and true. . . . By this means all knowledge degen- 
erates into probability. . . . There is no algebraist 
nor mathematician so expert in his science, as to place 
entire confidence in any truth immediately on his 
discovery of it, or regard it as any thing, but a mere 
probability. ... In accounts of any length or im- 
portance, merchants seldom trust to the infallible 
certainty of numbers for their security. ' ' And as no 
one will maintain "that our assurance in a long 
enumeration exceeds probability," Hume thinks he 
may "safely affirm, that there scarce is any proposi- 
tion concerning numbers, of which we can have a 
fuller security." If "any single addition were. cer- 
tain, every one would be so, and consequently the 
whole or total sum. ' ' But of course the whole is not 
certain. "Since, therefore," he concludes, 1 "all 
knowledge resolves itself into probability, and be- 
comes at last of the same nature with that evidence 
which we employ in common life, we must now ex- 
amine this latter species of reasoning, and see on 
what foundation it stands." 

In every judgment concerning probability, and con- 
sequently concerning knowledge— since "all knowl- 

1 P. 473. 



KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 119 

edge resolves itself into probability/'— there are, 
according to Hume, two sources of error and un- 
certainty, the understanding which judges, and the 
object about which the judgment is made. 1 Hence, 
even "the man of the best sense and longest experi- 
ence . . . [is] conscious of many errors in the past, 
and must still dread the like for the future. ' ' Hume 
contends that, because of this natural fallibility of 
the understanding, every judgment requires to be 
corrected by another judgment, this one by another 
and so on ad infinitum. Thus as "demonstration is 
subject to the control of probability," so is "proba- 
bility liable to a new correction by a reflex act of the 
mind, wherein the nature of our understanding, and 
our reasoning from the first probability become our 
objects." And he concludes again: 2 "When I reflect 
on the natural fallibility of my judgment, I have less 
confidence in my opinions, than when I only consider 
the objects concerning which I reason; and when I 
proceed still farther, to turn the scrutiny against 
every successive estimation I make of my faculties, 
all the rules of logic require a continual diminution, 
and at last a total extinction of belief and evidence." 
This is the logical account in Hume's treatment of 
mathematics,— or rather one might say of knowledge. 
For it has doubtless been noticed that, in following 
his order of exposition, the subject has been gradually 
broadened, until now the account applies not merely 
to mathematics but to knowledge in general. 

The foregoing passages have given rise to two dif- 
ferent lines of interpretation, neither of which is quite 
correct. According to the one, Hume distinguished 

1 P. 474. 2 iud.; cf. p. 475. 



120 hume's treatise and inquiry. 

between mathematics as a pure science and mathe- 
matics as an applied science, and maintained that the 
former possesses exact and demonstrative certainty, 
but the latter only probability. According to the 
other interpretation, Hume's doctrine of mathematics 
is the culmination of a system of absolute skepticism 
or nihilism. The former view prevails, to a consid- 
erable extent, among the German critics ; the latter is 
not uncommon with the writers of the Scottish school. 
They may be examined in succession. 

Windelband affirms: 1 "Mathematics is . . . the 
sole demonstrative science; and is that just because 
it relates to nothing else than the possible relations 
between contents of ideas, and asserts nothing what- 
ever as to any relation of these to a real world. In 
this way the terministic principle of Hobbes is in 
complete control with Hume, but the latter proceeds 
still more consistently with his limitation of this 
theory to pure mathematics." And Riehl asserts: 2 
"Hume doubts not the exactness of pure, but the 
validity of applied mathematics, ' ' This position has 
been controverted by Adamson. "No question," he 
declares, 3 "arises regarding the existence of the fact 
represented by the ideas, and in so far, at least, mathe- 
matical judgments may be regarded as hypothetical. 
. . . That the propositions are hypothetical in this 
fashion does not imply any distinction between the 
abstract truth of the ideal judgments and the imper- 
fect correspondence of concrete material with these 

1 History of Philosophy, p. 473 ; cf. Petzholtz, Die Haupt- 
punhte D. H. ErJcenntnislehre, p. 29. 

2 Der philosophische Kriticismus, I, pp. 96, 97. 
8 Ency. Brit., art. Hume, p. 353. 



KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 121 

ideal relations. Such distinction is quite foreign to 
Hume, and can only be ascribed to him from an entire 
misconception of his view regarding the ideas of space 
and time." The statement of Adamson is the more 
correct one. Not only does Hume fail to distinguish 
between "the abstract truth of the ideal judgments 
and the imperfect correspondence of concrete material 
with these ideal relations, ' ' but he denies that this dis- 
tinction exists. "[To reason]," he says, 1 "that the 
objects of geometry, . . . are mere ideas in the mind ; 
and not only never did, but never can exist in nature, ' ' 
is ' ' absurd and contradictory. ' ' Again, 2 ' ' The notion 
of any correction [in geometry] beyond what we have 
instruments and art to make, is a mere fiction of the 
mind, and useless as well as incomprehensible." 
Finally, he states conclusively: 3 "It is usual with 
mathematicians, to pretend, that those ideas, which 
are their objects, are of so refined and spiritual a 
nature, that they fall not under the conception of the 
fancy, but must be comprehended by a pure and in- 
tellectual view, of which the superior faculties of the 
soul are alone capable. . . . But to destroy this arti- 
fice, we need but reflect on that principle so often 
insisted on, that all our ideas are copied from our 
impressions." At the same time, it should be ob- 
served that, somewhat in accordance with the view 
expressed by Windelband and Eiehl, Hume recog- 
nized a distinction between arithmetic and algebra as 
exact and certain sciences, and the practical applica- 
tion of these sciences to concrete material. He re- 
peatedly asserted that arithmetic and algebra are 
perfectly exact and certain, 4 but that in practice "all 

I P. 3 18. ■ P. 353. 3 p. 375. a p p# 374^ 472 . 



122 hume's treatise and inquiry. 

knowledge degenerates into probability. ' n Further- 
more, tie said: 2 "In all demonstrative sciences the 
rules are certain and infallible; but when we apply 
them, our fallible and uncertain faculties are very apt 
to depart f r,om them, and fall into error. ' ' 

Controversy on this subject has arisen owing to the 
fact that Hume neglected to give a derivation of num- 
ber. Adamson, following in the wake of Green, in- 
sists that, on Hume's fundamental principles, a de- 
rivation of number suitable to serve as a foundation 
for mathematics cannot be given. "While on the other 
hand, "Windelband, recognizing that Hume held arith- 
metic and algebra to be perfectly exact and certain 
sciences, erroneously concludes that mathematics is a 
pure science. The truth of the matter seems to be 
this : not only is a derivation of abstract number pos- 
sible, in accordance with the principles of empiricism, 
but so also is a derivation of abstract quantity. For 
by means of approximations, abstraction, and gen- 
eralization, the transition is not difficult from the 
perception of r.eal lines and circles in nature to the 
ideas of perfectly straight lines and perfect circles 
corresponding to the definitions of geometry. Hume, 
neglecting to give a derivation of number, failed to 
show how arithmetic and algebra, as abstract sciences, 
are possible. Nevertheless, he rightly held that arith- 
metic and algebra are perfectly exact and certain. 
And he not only failed to give a derivation of quan- 
tity—pure or abstract quantity,— but contended that 
such could not be given, and hence mistakenly asserted 
that geometry is not an exact nor certain science. 
The position of many writers of the Scottish school, 
i Pp. 472, 473. 2 p. 472. 



KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 123 

that Hume 's theory of knowledge is a system of abso- 
lute skepticism, is of course unwarranted. True, in 
so far as they assert that absolute skepticism is the 
result of the strictly logical, as distinguished from the 
psychological factor in this theory of knowledge, they 
are literally correct. The author admits this himself. 
"When I proceed still farther," he says, 1 "to turn 
the scrutiny against every successive estimation I 
make of my faculties, all the rules of logic require a 
continual diminution, and at last a total extinction 
of belief and evidence. ' ' But Hume clearly perceived 
that the human mind did not always function in con- 
formity with the laws of logic. Then followed natur- 
ally his psychological account of mathematics,— or 
rather, it may be said, of knowledge in general. 

III. The Psychological Treatment of Mathematics. 
—The psychological element is a most important fac- 
tor, in Hume's theory of knowledge. It is the great 
head stone of the corner. It is not only an original, 
but a distinctively Anglo-Saxon contribution to phi- 
losophy. Pfleiderer has well said that "imagination 
and association are two genuine English powers, 
through which this people, on the ideal ground of 
poetry and in the magnificent arena of achievement, 
have brilliantly paid their tribute to the world's his- 
tory." Another tribute has similarly been paid in 
the subtle realm of speculative thought. 

After stating that the logical result of his episte- 
mological account of knowledge is a total extinction 
of belief and evidence, Hume proceeds: 2 "Should it 
here be asked me, whether I sincerely assent to this 
argument, which I seem to take such pains to incul- 

1 Pp. 474, 475. ■ p # 474. 



124 hume's treatise and inquiry. 

cate, and whether I be really one of those skeptics, 
who hold that all is uncertain, and that our judgment 
is not in any thing possessed of any measure of truth 
and falsehood; I should reply, that this question is 
entirely superfluous, and that neither I, nor any other 
person was ever sincerely and constantly of that opin- 
ion. Nature, by an absolute and uncontrollable neces- 
sity has determined us to judge as well as to breathe 
and feel. ' ' This determination of nature arises from 
custom or habit. From custom arises belief. And 
belief alone preserves the mind from total skepticism. 1 
But all demonstrative knowledge— arithmetic and al- 
gebra as well as geometry— is reduced to a species of 
probability. In short, the greatest degree of certainty, 
whether intuitive or demonstrative, is belief. "Belief 
is more properly an act of the sensitive, than of the 
cogitative part of our natures," 2 and the degree of 
conviction attending it— although at times the con- 
viction is delusive 3 — "is sufficient for oue purpose, 
either in philosophy or common life." 4 

IV. Conclusion.— The answers of the Treatise to 
the first three questions that demand settlement have 
now been indicated. The answer to the first, is an 
unqualified negative. Mathematics is not an a priori 
science, but empirical, because its first principles are 
sensible. The answer to the second question is a 
qualified negative. Is mathematics an absolutely cer- 
tain science? It depends upon the meaning attrib- 
uted to absolute. Mathematics is not an absolutely 
certain science, in the sense of being a priori certain. 
For the human mind is finite ; knowledge is relative ; 
and in nearly all thinking processes there is a possi- 

i P. 475. 2 iud. 3 Cf. pp. 545, 547. * P. 476. 



KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 125 

bility of error. But arithmetic and algebra are em- 
pirically certain. Geometry, of course, is not. In 
certain passages, however, it is said that arithmetic 
and algebra are perfectly exact and certain sciences. 1 
Yes, those statements are in the epistemological ac- 
count, and are to be understood, therefore, in a pro- 
visional or relative sense. In the psychological ac- 
count, Hume holds that these sciences are practically, 
or empirically certain, not absolutely or a priori cer- 
tain. The answer to the third question is a divided 
one. Arithmetic and algebra are perfectly exact sci- 
ences; on the other hand, geometry is not. 

§ 23. Treatment of Mathematics in the Appendix. 
—In the appendix Hume added a few remarks on 
geometry, for the purpose of further explaining his 
meaning. These passages do not indicate any change 
of view from that expressed in the Treatise, and con- 
sequently, do not require extended comment. There 
is but one statement that seems to call for a word of 
explanation. "If [mathematicians] employ," says 
the author, 2 "as is usual, the inaccurate standard, 
derived from a comparison of objects, upon their gen- 
eral appearance, corrected by measuring and juxta- 
position; their first principles, though certain and 
infallible, are too coarse to afford any such subtile 
inferences as they commonly draw from them. ' ' Here 
he speaks of the first principles of geometry as being 
"certain and infallible/ ' whereas, in the Treatise he 
had regarded them as being inexact, and not precisely 
true 3 The inconsistency is only verbal. In the ap- 
pendix he does not mean, literally, that the first prin- 

1 P. 374. 2 p. 357. 

3 Of. pp. 350, 350, 373, 374. 



126 hume's treatise and inquiry. 

ciples of geometry are "certain and infallible," for 
he not only says that they are "too coarse" to afford 
such "subtile inferences" as are commonly drawn 
from them, but he immediately adds that they "are 
founded on the imagination and senses." And in 
another passage he asserts 1 "that the only useful no- 
tion of equality, or inequality, is derived from the 
whole united appearance and the comparison of par- 
ticular objects." 

§ 24. Treatment of Mathematics in the Inquiry.— 
In the Inquiry, on the subject of mathematics, there 
is at once observable a great difference in the form 
of statement. Since Hume omits that portion of the 
Treatise which deals with space and time, and conse- 
quently neglects to give a derivation of space, as he 
did formerly to give a derivation of number, the sci- 
ences of arithmetic, algebra, and geometry seem to 
stand upon the same basis of exactness and certainty ; 
and since he omits the account of philosophical rela- 
tions, the former distinctions between the different 
degrees of evidence not only fall into the background, 
but almost entirely disappear. The obvious result is 
that the author, appears to have approached, if not to 
have adopted, the common sense view of mathematics. 2 
He divides "all the objects of human reason or in- 
quiry" into relations of ideas and matters of fact; 
and under relations of ideas he includes the sciences 
of arithmetic, algebra, and geometry, "and in short, 
every affirmation, which is either intuitively or demon- 
stratively certain." 3 The propositions of mathe- 

iP. 352. 

2 Cf. pp. 107, 108, above. 

» P. 20; cf. p. 22, 135. 



KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 127 

matics, he holds, "are discoverable by the mere opera- 
tion of thought, without dependence upon what is any- 
where existent in the universe. Though there never 
were a circle or triangle in nature, the truths, demon- 
strated by Euclid, would for ever retain their cer- 
tainty and evidence." 1 

The foregoing statement summarizes Hume's treat- 
ment of mathematics in the Inquiry. It corresponds 
to the epistemological account in the Treatise. Both 
the logi3al and psychological accounts are omitted in 
the later work. Naturally, therefore, it has been al- 
most universally supposed that there is a fundamental 
difference between the doctrine of mathematics in the 
Inquiry and that in the Treatise. The supposition, 
however, is without foundation. Had the logical and 
psychological accounts not been omitted, it is prac- 
tically certain that the position of both works, on this 
question, would have been identical. But why are 
these accounts omitted ? it may be asked ; does not this 
fact in itself indicate a change of view? Not neces- 
sarily, for Hume was here giving a popular exposition 
of the more easy and interesting parts of his system, 
and he reserved mathematics for special treatment 
on another, occasion. Later, he wrote an essay on 
"The Metaphysical Principles of Geometry/' but did 
not publish it, because Lord Stanhope convinced him 
that " either there was some defect in the argument, 
or in its perspicuity." 2 Even in default of this essay, 
there are several incidental references in the Inquiry 
which £ro far to prove that his view of mathematics is 
still essentially the same as that presented in the 
Treatise. 

1 P. 22; c/\ pp. 10 n., 28, 37, 50, 51, 131. 
2 <'f. pp. 96, 1)7, above. 



128 hume's treatise and inquiry. 

Arithmetic, algebra, and geometry are not a priori 
sciences, but empirical. For Hume, in accordance 
with his principle that all ideas are copies of impres- 
sions, states explicitly that "the ideas of the mathe- 
matical sciences, being sensible, ' ' are always clear and 
determinate. 1 ' ' All the ideas of quantity, ' ' he thinks, 2 
"upon which mathematicians reason, are nothing but 
particular, and such as are suggested by the senses 
and imagination." Since, therefore, the mathemat- 
ical sciences are empirical, they are not absolutely or 
a priori certain. ' ' One may safely, ... affirm, ' ' 
says Hume, 3 "that if we consider, [the moral and 
mathematical sciences] in a perfect light, their ad- 
vantages and disadvantages nearly compensate each 
other, and reduce both of them to a state of equality. ' ' 
The general view just indicated will be confirmed by 
a special consideration of geometry,— that branch of 
mathematics being treated somewhat more fully than 
is arithmetic or algebra. 

It has already been shown 4 that although Hume, 
in the Inquiry, omitted the treatment of space and 
time, yet his doctrine of space and time is similar in 
both works. It is not surprising, therefore, that he 
looks upon geometry as an empirical science. His 
position, as stated in section iv, corresponds with that 
of Hobbes. His meaning is, that "the truths" dem- 
onstrated by Euclid "for ever retain their certainty 
and evidence," after knowledge of the geometrical 
figures has once been acquired. Since, however, all 
geometrical figures are sensible, a knowledge of them 
is derived only through sense experience. In short, 
geometry in an inductive science. But it differs from 

i P. 50. 2 p. 129 n. 3 p. 50. 4p p . 95-97. 



KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 129 

other inductive sciences in the fact that one instance 
serves as a sufficient basis for a generalization. ' ' The 
conclusions, which [reason] draws from considering 
one circle, are the same which it would form upon 
surveying all the circles in the universe." 1 Kant, it 
is true, mistakenly supposed Hume to regard geom- 
etry—or rather mathematics— as an analytical science. 
For this opinion, indeed, Hume gave some ground 
when he affirmed that the equality of the square on 
the hypothenuse of a right angled triangle to the 
squares on the two sides was a relation, "discoverable 
by the mere operation of thought. ' ' But he explained 
his meaning when he declared that this relation could 
not "be known, let the terms be ever so exactly de- 
fined, without a train of reasoning and inquiry." 2 

Not only is geometry, as treated in the later work, 
an empirical science, but it is not a perfectly exact 
science. In the editions of 1748 and 1751, in a note 
appended to the twelfth section, Hume asserts: 3 "In 
general, we may pronounce, that the ideas of greater, 
less, or equal, which are the chief objects of geometry, 
are far from being so exact or determinate as to be the 
foundation of such extraordinary inferences [as those 
arising from the doctrine of the infinite divisibility of 
space]. Ask a mathematician what he means, when 
he pronounces two quantities to be equal, and he must 
say, that the idea of equality is one of those, which 
cannot be defined, and that it is sufficient to place two 
equal qualities before any one, in order to suggest it. 
Now this is an appeal to the general appearances of 
objects to the imagination or senses, and consequently 

1 1*. 37 j c(. Brede, Dcr Untersohied d. Lehren 1L, p. 35. 

2 P. 134. 3 p. 129 n. 





130 hume's treatise and inquiry. 

can never affor.d conclusions so directly contrary to 
these faculties. ' ' This passage was omitted after the 
edition of 1751, but the remainder of the note was 
retained. It contains the following sentences: "If 
this be admitted [that there is no such thing as ab- 
stract or general ideas] (as seems reasonable) it fol- 
lows that all the ideas of quantity, upon which mathe- 
maticians reason, are nothing but particular, and such 
as ar.e suggested by the senses and imagination, and 
consequently cannot be infinitely divisible. It is suffi- 
cient to have dropped this hint at present, without 
prosecuting it any farther. ' ' Now if all the ideas of 
quantity are "nothing but particular, and such as are 
suggested by the senses and imagination, " it is evident 
that geometry is not a perfectly exact science. That 
it contains "contradictions and absurdities/' Hume 
explicitly affirms, if it be assumed that there are gen- 
eral ideas. He denies the assumption, however, and 
in that manner thinks to escape the contradictions. 
Yet his attempt to do this in the essay on i ' The Meta- 
physical Principles of Geometry" does not appear, to 
have been successful. 

Finally, it must be observed, that although Hume, 
in the Inquiry, omitted a specific criticism of reason 
and the senses, he said enough to indicate that the 
logical treatment of mathematics was omitted in the 
later work, not because he had changed his opinions 
on this subject, but because no "durable good or 
benefit to society" could be expected to result from 
such criticism. 1 Thus he asserts: 2 "The chief objec- 
tion against all abstract reasonings is derived fr.om the 
ideas of space and time ; ideas, which, in common life 

1 P. 131. t Pp. 128, 129. 



KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 131 

and to a careless view, are very clear and intelligible, 
but when they pass through the scrutiny of the pro- 
found sciences . . . afford principles, which seem 
full of obscurity and contradiction. . . . The demon- 
stration of these principles seems as unexceptionable 
as that which proves the three angles of a triangle to 
be equal to two right ones, though the latter opinion 
be natural and easy, and the former big with contra- 
diction and absurdity. Reason here seems to be 
thrown into a kind of amazement and suspense, . . . 
She sees a full light, which illuminates certain places ; 
but that light borders upon the most profound dark- 
ness. And between these she is so dazzled and con- 
founded, that she scarcely can pronounce with cer- 
tainty and assurance concerning any one object." 
Even with regard to "the skeptical objections" to the 
reasonings concerning matters of fact, the author de- 
clares that, "while the skeptic insists upon these 
topics, he shows his force, or rather, indeed, his own 
and our weakness ; and seems, for the time at least, to 
destroy all assurance and conviction." 1 But of 
course, as before, nature comes to the assistance of 
reason. The great subverter of "excessive skepti- 
cism" is action. Nature is always too strong for prin- 
ciple- An evident implication of these passages is 
that although the mathematical sciences possess em- 
pirical certainty, no science possesses absolute or a 
priori certainly. 

It is now manifest that Hume's view of mathe- 
matics, in the Inquiry, is substantially the same as 
thai in the Treatise. Arithmetic, algebra, and geom- 
etry arc not a priori sciences, but empirical; for "the 

■P. 131. tlhitl. 



/ 



132 hume's treatise and inquiry. 

ideas" of "the mathematical sciences/' having been 
derived from impressions, are "sensible." 1 Arith- 
metic, algebra, and geometry are not absolutely or 
a priori certain sciences, for the advantages and 
disadvantages of the mathematical and moral sciences 
"nearly compensate each other, and reduce both of 
them to a state of equality." 2 And geometry is not 
a perfectly exact science, for "all the ideas of quan- 
tity, . . . are nothing but particular, and such as 
are suggested by the senses and imagination. ' ' 3 But 
Hume says that arithmetic, algebra, and geometry are 
"intuitively or, demonstratively certain." 4 Very 
true; this is in his epistemological account. He 
made the same statement in the Treatise. He does 
not mean, of course, that the mathematical sciences 
are a priori intuitively or demonstratively certain. 
But he asserts that propositions in mathematics "are 
discoverable by the mere operation of thought." 5 
Yes, he means after the ideas have been derived from 
sensible objects. Yet he also affirms, that "the only 
objects of the abstract sciences or of demonstration 
are quantity and number"; 6 that these sciences are a 
"more perfect species of knowledge" 7 than are mat- 
ters of fact; and that they are "the only proper ob- 
jects of knowledge and demonstration." 8 In all these 
statements Hume, from his point of view, is perfectly 
correct. It is the traditional philosopher who is in 
error in inferring from them a priori exactness and 
certainty, through reading the thoughts of rationalism 
into the wor.ds of Hume. 

§25, References to Mathematics in Hume's other 



i P. 50. 


* Ibid. 


3 P. 129 n. 


* P. 20. 


5 P. 21. 


■ P. 133. 


» im. 


s P. 134. 



KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 133 

Philosophical Works. — It avails little to appeal to 
Hume's other philosophical writings for additional 
information on this subject. Yet if such reference 
be made, it tends, on the whole, to confirm the con- 
clusion that has already been arrived at. In the 
Treatise of the Passions the author states: 1 "The con- 
clusions [concerning the relations of ideas] are equally 
just, when we discover the equality of two bodies by 
a pair of compasses, as when we learn it by a mathe- 
matical demonstration ; and though in the one case the 
proofs be demonstrative, and in the other only sensi- 
ble, yet generally speaking, the mind acquiesces with 
equal assurance in the one as in the other." In the 
Treatise of Morals, 2 "If you assert, that vice and vir- 
tue consist in relations susceptible of certainty and 
demonstration, you must confine yourself to those four 
relations, which alone admit of that degree of evi- 
dence. ' ' In the Inquiry concerning the Principles of 
Morals? "It would be absurd ... to infer, that the 
perception of beauty, like that of truth in general 
problems, consists wholly in the perception of relations, 
and was performed entirely by the understanding or 
intellectual faculties. " In the Dialogues concerning 
Natural Religion, 4 "Let the errors and deceits of our 
very senses be set before us; the insuperable difficul- 
ties, which attend first principles in all systems; the 
contradictions, which adhere to the very ideas of mat- 
ter, cause and effect, extension, space, time, motion; 
and in a word, quantity of all kinds, the object of the 
only science, that can fairly pretend to any certainty 
or evidence;' 1 In short, the statements in the treatise 
on Tin Passions and in the Dialogues imply that the 
IH, p. 223. MI, p. 240. 3 IV, p. 2G3. « II, p. 381. 



134 hume's treatise and inquiry. 

mathematical sciences are empirical, and that geom- 
etry is not exact ; but those in the treatises on Morals 
do not seem to have exactly the same implication, al- 
though they have not necessarily a contrary one. 

The difference just noticed between the statements 
on mathematics in the treatise of The Passions and 
the Dialogues, and in the treatises on Morals is easily 
explained. Not only was Hume exceedingly indefi- 
nite in his use of terms, but he did not recognize the 
same criterion of truth when discussing theoretical 
subjects, as when discussing practical subjects. Re- 
plying to Elliot,— who held that "an instinctive feel- 
ing" in the intellectual part of one's nature, "re- 
sembling the moral instinct in the moral part/' 
corrects over refinement of subtlety or speculation,— 
he wrote: 1 "Your notion of correcting subtlety of 
sentiment, is certainly very just with regard to morals, 
which depend upon sentiment; and in politics and 
natural philosophy, whatever conclusion is contrary 
to certain matters of fact, must certainly be wrong, 
and there must some error lie somewhere in the argu- 
ment, whether we be able to show it or not. But in 
metaphysics or theology, I cannot see how either of 
these plain and obvious standards of truth can have 
place. Nothing there can correct bad reasoning but 
good reasoning. And sophistry must be opposed by 
syllogisms. ' ' 

§ 26. Conclusion.— The results of the discussion 
may be summarized as follows:— 

1. The Faculties of Mind.— The more important 
mental faculties recognized by Hume ar.e sensation, 
memory, imagination, reason, reflection, and instinct. 

i Burton, Life, 1, p. 324. 



KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 135 

He did not systematically classify, nor accurately de- 
fine them. He often experienced difficulty in de- 
scribing what he had in mind, and used, in both works, 
not only a variety of terms, but also, at different times, 
different terms to express the same thing. Most no- 
tably is this the case with regard to imagination and 
instinct. Knowledge begins with sensation. Mem- 
ory, imagination, and reason represent different stages 
of the same process. Reflection is a peculiar mixture 
of thinking and feeling. Instinct is not definable. It 
is often identified with imagination, habit, custom, or 
nature, and includes all those processes that cannot 
otherwise be explained. 

The only significant change, in the Inquiry, occurs 
in the treatment of instinct. Here Hume takes a 
place among modern psychologists. Instinct, having 
encroached on the domains of imagination, habit, and 
custom, becomes the faculty, par excellence. It mani- 
fests itself, at least by implication, below the level of 
consciousness, as tendencies to react upon the environ- 
ment. It subsists side by side with sensation, mem- 
ory, imagination, and reason, as impulses to action, 
and it appears at the higher end of consciousness, 
transcending reason, as the ultimate ends of action, 
ends for which reason can assign no reason. 1 In this 
last sense, instincts— according to Hume,— or ideals of 
reason— according to the rationalistic philosophers,— 
are the assertion of the whole mind, the expression of 
the entire life of the individual. As such, they vary 
according to the stage of development of the person, 
of the community, of the nation, of the race. As 
jxM.pl.' advance in civilization, contradictions natu- 

1 Of. Everett, Essays: Theological and Literary, chs. I, VII. 



136 hume's treatise and inquiry. 

rally and necessarily arise between imagination and 
reason, and between reason and instinct. Hume saw 
clearly that, in a world of progress, the solution of all 
the contradictions of human experience is absolutely 
impossible. And he does not seem to have been far 
from the right track when he regarded the solution of 
these contradictions, so far as that is possible, to lie 
largely within the functions of imagination and in- 
stinct. In the treatment of his problem, however, he 
soon encountered insuperable difficulties, because biol- 
ogy, which opens the ante-room of psychology, was 
unable to lift the latch, being only in its infancy in 
his day. 

2. Intuitive Knowledge.— In the Treatise, intuitive, 
or sense and memory knowledge is based on the philo- 
sophical relations of resemblance, contrariety, and 
degr.ees of quality, and arises immediately from the 
observation, or comparison of impressions and ideas. 
It is not necessarily exact, nor certain, but is condi- 
tioned by the nature of the object observed, and the 
capacity of the mind observing. In the Inquiry, the 
classification of philosophical relations is omitted, and 
naturally also a treatment of intuitive knowledge ; yet 
on this latter question, Hume's view, by implication, 
seems to be the same as f orjnerly. 

3. Demonstrative Knowledge.— Mathematics, or 
knowledge developed by reason, is based on the philo- 
sophical relation of proportions in number and quan- 
tity. In the Treatise, Hume gave three different, 
although not distinct or separate expositions of mathe- 
matics: an epistemological account in Parts II and 
III, a logical, and a psychological account in Part IV. 
According to the epistemological account, mathematics 



KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 137 

is an empirical science, because the ideas of number 
and quantity are derived from the senses; arithmetic 
and algebra are perfectly exact and certain sciences, 
because they possess a "precise standard"; but geom- 
etry is not an exact or certain science, because its first 
principles are based upon the general appearances of 
objects to the senses and imagination. According to 
the logical account, "all knowledge degenerates into 
probability, " and would at last, were it not for the 
influence of custom, result in "a total extinction of 
belief and evidence. " The psychological account pro- 
fesses to show how judgments in the mathematical 
sciences, like those in any other science, retain a cer- 
tain amount of assurance. Custom, or imagination, 
or instinct, or nature determines one by "an absolute 
and uncontrollable necessity " to judge and to believe, 
as well as to breathe and feel. The degree of belief 
attending the judgment is, of course, greater, in short 
and simple problems than in long and intricate ones. 
But in all cases, the quality or character of belief is 
the same, belief being "more properly an act of the 
sensitive, than of the cogitative part of our natures. " 
In the Inquiry the logical and psychological ac- 
counts of mathematics are omitted. Hence, it has 
been the common opinion that Hume, in the later 
work, regarded mathematics as an absolutely certain 
science, based on a priori principles. And since, in 
the brief epistemological account that is given, arith- 
metic, algebra, and geometry seem to stand on an 
equal footing, the rationalistic philosophers, in ac- 
cordance with their favorite presuppositions, natu- 
rally thought that Hume had elevated geometry to 
the rank of an exact science. On the contrary, how- 



138 hume's treatise and inquiry. 

ever, the facts of the matter are, that he first regarded 
arithmetic and algebra as being on an empirical basis 
equally with geometry, and later modified his episte- 
mological account to such an extent as to show that 
mathematics is not an absolutely certain science, and 
that geometry is not a perfectly exact one. 

The four questions proposed at the beginning of 
the discussion ar.e now answered. (1) According to 
Hume, mathematics is not an a priori science; (2) it 
is not an absolutely certain science; (3) geometry is 
not a perfectly exact science; and (4) this seems to 
be the position of both the Treatise and Inquiry. It 
only remains yet to add a remark explanatory of the 
fourth answer, for as here stated, it is liable to mis- 
conception. Although it is true that, in neither wort, 
is mathematics an a priori, or an absolutely certain 
science, nor is geometry a perfectly exact one ; it does 
not follow, by any means, that the general positions 
of the two works, on this subject, are identical. Log- 
ically, they are ; actually, they are not. Although the 
doctrine is essentially the same in the Inquiry as in 
the Treatise, the statement of it, as has repeatedly 
been pointed out, is quite different. And in this case, 
the difference in statement is so great that, without 
implying any change of view on the part of the author, 
it produces a very remarkable change in the tone and 
attitude of the book. While the doctrine of the 
Treatise is stated fully and boldly, that of the Inquiry 
is expressed briefly and hesitatingly. Yet the differ- 
ences in the later work are only of such a nature as 
can easily be explained. They arise from the omis- 
sion of the logical and psychological accounts of 
mathematics. And these omissions were made be- 



KNOWLEDGE, INTUITIVE AND DEMONSTRATIVE. 139 

cause: (1) Hume aimed, in the Inquiry, to give a 
brief and popular exposition of his theory of knowl- 
edge; (2) he intended to deal with mathematics at 
some future time; and (3) he thought that no "dur- 
able good or benefit to society" could be expected to 
result from a detailed statement of the skeptical ob- 
jections against reason or the senses. 

When Hume maintains that mathematics is an em- 
pirical science, and consequently, not possessed of 
absolute or a priori certainty, he is indubitably right. 
But when, through his failure to perceive that the 
fundamental characteristic of general ideas is the 
epistemological element, he contends that geometry is 
not a perfectly exact science, he is unquestionably 
wrong. As Aristotle held that, in any science, one 
should expect only that degree of accuracy which is 
conformable to the nature of the subject; so Hume 
held that the different sciences, being all empirical, 
admit of varying degrees of exactness and certainty, 
according to the nature of the subject-matter. But 
Hume, again like Aristotle, did not succeed, in all 
respects, in carrying out his principle. The limita- 
tions of his time, and his own psychical predisposition 
—his visualizing imagination,— were obstacles too 
great for his philosophical genius entirely to overcome. 



CHAPTER VII. 

THE IDEA OF CAUSE AND EFFECT. 

§ 27. Causation the Basis of Reasoning Concern- 
ing Matters of Fact.— The idea of causation has been 
an object of reflection ever since the dawn of rational 
speculation, and the validity of belief in causality has 
frequently been questioned throughout the history of 
philosophical inquiry. Egyptian and Jewish, Hindoo 
and Persian, Greek and Roman,— all historical races 
have had their distinctive representatives of empiri- 
cism and skepticism. It is in English philosophy, 
however, by intensely practical men, that the idea of 
cause and effect has been subjected to the most search- 
ing examination. Glanvill affirmed emphatically, that 
necessary connection is not perceivable by the senses. 
Hobbes, Locke, and Berkeley followed, more or less 
closely, along the same line of Pyrrhonism. They 
prepared the way for, Hume. And although Hume, 
in his criticism of the idea of cause and effect, did 
little more, perhaps, than sum up and present in a 
new form the logical results of his predecessors' re- 
flection; nevertheless, to him belongs the distinctive 
honor of being the first philosophical writer, who gave 
a final analysis of the conception of causality from 
the standpoint of pur.e empiricism. Hume's exam- 
ination of the idea of cause and effect is not only an 
invaluable contribution to speculative thought, but 
also an imperishable monument to the intellectual 
acumen and subtle analytical power of one of the 
greatest of the many keen thinkers of Scotland. 

140 



THE IDEA OF CAUSE AND EFFECT. 141 

Cause and substance are the two poles of the phi- 
losophy of human nature. Having treated intuitive 
knowledge and demonstrative, Hume proceeded to 
deal with that division of probability which he calls 
proofs, reasoning proper, moral, or experiential. 
This species of reasoning is conversant with matters 
of fact. It is not, like intuitive and demonstrative 
knowledge, founded on the relations of resemblance, 
contrariety, degrees of quality, and proportions in 
number, or quantity ; for since the contrary of matters 
of fact is conceivable, and therefore possible, knowl- 
edge of them is not obtained by means of reason. 
Nevertheless, the "arguments" in experiential, or 
empirical reasoning are regarded as being "entirely 
free from doubt and uncertainty." 1 

All reasoning is of the nature of comparison. In 
comparison, one of the two objects compared, or 
neither, or both may be present to the senses or 
memory. 2 If neither object is present, the reasoning 
is purely hypothetical. 3 This statement is analogous 
to Kant's famous dictum, "concepts without percepts 
are empty." When the two objects are present to 
the senses or memory, the act is called "perception 
rather, than reasoning." Similarly Kant said that 
"percepts without concepts are blind." When the 
two objects are present to sense or memory, the com- 
parison is based on the relations of identity and con- 
tinuity. 4 But in instances of comparison when only 
one object is present to the senses or memory, there 
is a conclusion drawn beyond experience. This is 

>oning proper, or experiential reasoning. Its basis 

»I, p. 423. 2i ? pp. 370, 384, 385; IV, p. 39. 

■I, pp. 384, 385, 390; IV, p. 39. «I, p. 37G. 



142 hume's treatise and inquiry. 

is the relation of cause and effect. 1 In order, there- 
fore, to discover the evidence for reasoning concern- 
ing matters of fact; that is, to learn the rational 
ground of experiential reasoning, it is necessary to 
examine the idea of cause and effect. 2 

§ 28. Examination of the Idea of Cause and Effect. 
—The treatment of causation, in the two works, al- 
though similar in form, differs much in detail. In 
the Treatise, the discussion is exceedingly thorough, 
systematic, and ingenious. In the Inquiry, on the 
other hand, it is brief and comparatively simple;— 
chiefly, no doubt, because Hume was afraid that 
should he "multiply words about it, or throw it into 
a greater variety of lights, it would only become mor.e 
obscure and intricate." 3 Pfleiderer 4 states that the 
argument in the Treatise, like that on causation in 
Kant 's Kritik, proceeds analytically, while the reason- 
ing in the Inquiry, as in the Prolegomena, proceeds 
synthetically. Rather it should be said, that the 
argument in both cases is essentially analytical, but 
in the later work the analysis is less prominent than 
in the earlier. 

In accordance with his usual method of argumenta- 
tion, Hume, in both works, opens the discussion by 
inquiring after the origin of the idea. 5 On this line 
of attack upon rationalism he had often won, and he 
again feels confident of achieving his wonted success. 
In the Inquiry, he states briefly, and then proceeds 
to prove, that the knowledge of the relation of cause 
and effect is not attained by intuitive perception, nor 

i 1, p. 376; IV, p. 24. *I, p. 377; IV, p. 24. sP. 63. 

^Empirismus u. Skepsis, p. 169 and n, 
61, p. 377; IV, p. 24. 



THE IDEA OF CAUSE AND EFFECT. 143 

by a priori reasoning, "but arises entirely from ex- 
perience." 1 In the Treatise, Hume is at his best in 
the discussion of causation. Slowly and thoroughly 
he prepares for an exhaustive analysis of his problem, 
and then, with rare skill and subtle penetration, he 
winds his tortuous way through an argument of 
nearly one hundred pages, until finally he reaches his 
intended goal. It may be thought that the idea of 
cause and effect is derived by means of the senses, or. 
by means of reason, or by means of a supra-natural 
power, or by means of the imagination. These are 
the only possible sources; and Hume examines them 
all. He first asserts that the impression of causation 
is not perceived as a quality of objects ; consequently, 
the idea "must be derived from some relation among 
objects. " 2 Next he inquires what relations are dis- 
coverable between objects that are "considered as 
causes or effects." These are two: (1) contiguity, 
(2) succession. 3 It is supposed, how r ever, that there 
is still another element in causation, viz., necessary 
connection; that is, that there is a necessary connec- 
tion between objects or events that are causally re- 
in ted. Moreover, it is the element of necessary con- 
nection which is always regarded as the essential part 
of causality. Hence this is the peculiar problem to 
be investigated. 4 But necessary connection among 
objects or events is not perceived by the senses either 
as a quality, or as a relation. Then Hume deems it 
advisable "to leave the direct survey" of the ques- 
tion, and "beat about all the neighboring fields." In 
tin's manner he hopes to find "a hint" that may serve 
to clear up the difficulty. 5 He soon discovers a clue 

'Pp. 24,25. 2P. 377. 3 rp. 377,, 378. «1\ 371). 'P. 380. 



144 hume's treatise and inquiry. 

in two questions bearing on the subject, one the gen- 
eral question of causation, the other the particular 
question. These two questions he then examines in 
succession ; whereupon, he comes back to the point at 
which he turned aside, and deals directly with the 
idea of necessary connection. Accordingly, the treat- 
ment of the relation of cause and effect falls into 
three main divisions:— 

I. The general question of causation. 1 
II. The particular question of causation. 2 

III. The idea of necessary connection. 3 
The accounts in both works may be examined to- 
gether. 

I. The general Question of Causation. The gen- 
eral question of causation is stated in the Treatise as 
follows: 4 "For what reason we pronounce it neces- 
sary, that every thing whose existence has a begin- 
ning, should also have a cause ? ' ' and in the Inquiry : 5 
"What is the foundation of all our reasonings and 
conclusions concerning [the relation of cause and 
effect]?" These two questions, though differently 
expressed, are essentially the same. Huxley 6 asserts 
that the evidence by which Hume supports his con- 
clusion in the Inquiry, concerning the general ques- 
tion of causation, "is not strictly relevant to the 
issue. " And several writers 1 state that he omits al- 

i I, pp. 380-^383; IV, pp. 24-38. 

2 1, pp. 383-422; IV, 24-47. 

3 I, pp. 450-466; IV, pp. 50-65. 

4 P. 380. s p. 28. e Hume, p. 118. 

7 Cf. Selby-Bigge, Hume's Enquiries, Introd.; Ueberweg- 
Heinze, Gesch. d. Phil., Ill, p. 201; Kiehl, Der philosophische 
Kriticismus, I, p. 114 and n.; Vaihinger, Kommentar m 
Kant's Kritile, I, pp. 347, 349. 



THE IDEA OF CAUSE AND EFFECT. 145 

together the consideration of this question in the later 
work. Now it may be admitted that part, at least, 
of the evidence by which he supports his conclusion 
in the Inquiry is not strictly relevant. But it is 
contended that the two questions, as above stated, 
are for Hume's purposes practically equivalent. 1 
They imply each other, in such a manner that the 
answer to both is the same. 

In the Treatise, the author professes to show that 
neither intuition, nor demonstration,— neither the 
senses and memory, nor thought and reasoning— is 
the ground of the opinion that every effect must have 
a cause. For if the necessity of a cause for every 
effect could be intuitively perceived, or could be 
demonstrated by reason, the contrary would be in- 
conceivable. But that the contrary is not inconceiv- 
able, he claims to prove by the following argument: 2 
"As all distinct ideas are separable from each other, 
and as the ideas of cause and effect are evidently dis- 
tinct, it will be easy for us to conceive any object to 
be non-existent this moment, and existent the next, 
without conjoining to it the distinct idea of a cause 
or productive principle.' ' Accordingly, he concludes 
that the opinion of the necessity of a cause for every 
effect arises wholly from "observation and experi- 
ence." 1 In the Inquiry,* Hume asserts that "the 
knowledge" of the relation of cause and effect "is 
not, in any instance, attained by reasonings a priori," 
nor by the intuitive perception of the qualities of 
objects, "but arises entirely from experience." His 
chief argument is similar to that in the Treatise: 

Wf. Caird, The Critical Phil, of Kant, I, p. 133 n.; Jalm, 
D. 11. OoJUsaMt&Mheorie, pp. 6, 41. 

■P. 381. IP. 3o3. *P, 24. 

10 



146 hume's treatise and inquiry. 

" Every effect is a distinct event from its cause." 1 
Consequently, it follows that " there is not, in any 
single, particular instance of cause and effect, any 
thing which can suggest the idea of power or neces- 
sary connection. ' ' 2 Of course when one abandons the 
atomistic view of mind, the petitio principii in this 
reasoning becomes obvious. But on Hume's presup- 
positions the argument is perfectly valid. If " every 
effect is a distinct event from its cause," or if it is 
easy "to conceive any object to be non-existent this 
moment, and existent the next, without conjoining to 
it the distinct idea of a cause or productive principle, ' ' 
there is no real necessity to think that every effect 
must have a cause ; and the supposed necessity, so far 
as it exists, must be explained on the ground of ex- 
perience. 

The next question should naturally be, how experi- 
ence gives rise to the opinion, that "whatever begins 
to exist, must have a cause of existence?" 3 But in 
the Treatise, Hume finds it "more convenient to sink 
this question" in the particular problem of causation, 
remarking: "It will, perhaps, be found in the end, 
that the same answer will serve for both." And in 
the Inquiry, instead of asking how experience gives 
rise to the principle that every event must have a 
cause? he asks a related question, viz., "What is the 
foundation of all conclusions from experience?"* 
These two questions, that of the Treatise and that of 
the Inquiry, may now be considered. 

II. The particular Question of Causation. The 
particular question of causation resolves itself into 
i P. 27. 2R 52. ap. 383. 4 p. 28. 



THE IDEA OF CAUSE AND EFFECT. 147 

three parts: 1 (1) "Why we conclude, that such par- 
ticular causes must necessarily have such particular 
effects?" (2) "AVhat is the nature of that inference 
we draw from the one to the other ?" (3) What is 
the nature of "the belief" we repose in the inferred 
idea ? The last of these problems will be left for con- 
sideration in the following chapter. The first ques- 
tion does not receive separate treatment, but is dealt 
with incidentally in connection with the second, Hume 
making the characteristic remark: "Perhaps it will 
appear in the end, that the necessary connection de- 
pends on the inference, instead of the inference de- 
pending on the necessary connection." 2 Consequently, 
the subject of immediate interest is the second division 
of the particular question of causation, viz., "Why 
we form an inference from one [instance] to an- 
other ? ' ' And this question, it may be noted, resolves 
itself into that of the Inquiry at present under in- 
vestigation; for the reason or ground on which we 
form an inference from one instance to another is, 
according to Hume, ' ' the foundation of all conclusions 
from experience." 

The argument may now be presented in two forms, 
as the mode of reasoning is not exactly the same in 
both works. This change of method, however, seems 
to have arisen from Hume's different ways of stating 
the problem, or perhaps from his desire for brevity 
of treatment in the Inquiry. In the Treatise, 3 the 
author gives a brief account of experience, professing 
to show how, from the observation of antecedent and 
consequent in a number of particular instances, the 
idea of cause and effect gradually arises. The infer- 

»I, pp. 380, 383. H, p. 389. iPp. 388, 389. 



148 hume's treatise and inquiry. 

ence, therefore, from cause to effect, or fr.om effect to 
cause is a transition of the mind from "a present 
impression of sense or memory' ' to a related idea. 
And the transition is founded, not on such a penetra- 
tion into the "essences" of objects "as may discover 
the dependence of the one upon the other," but on 
past experience. Then the question occurs, whether, 
the transition is produced by reason, or by imagina- 
tion ? x Were it produced by reason, it would be based 
on the principle of the uniformity of nature. Hence 
the following question presents itself, what is the 
ground of the principle of the uniformity of nature? 
This principle is not established on intuitive knowl- 
edge, nor on demonstrative,— that is, it is not derived 
from the senses, nor from reason,— because a change 
in the course of nature is conceivable. Neither is it 
derived from probability, for probability is founded 
upon it. Bather it arises fr.om constant conjunction 
or custom, and is, therefore, an assumption that can 
never be proved. 3 Consequently, the transition or 
inference is not produced by reason, but by imagina- 
tion, by means of the two primary laws of association, 
resemblance and contiguity, that is, through the repe- 
tition of similar, instances or custom. 4 

According to the Inquiry, all conclusions from ex- 
perience "proceed upon the supposition, that the 
future will be conformable to the past." 5 But then 
it must be asked, as before, what is the ground of the 
principle of the uniformity of nature? This prin- 
ciple does not rest upon demonstrative arguments, 

iR 390. 2p. 391. spp. 392, 431, 545. 

Wf. pp. 390, 393, 403, 414, 459, 461, 471, 509. 
5Pp. 29, 31, 33. 



THE IDEA OF CAUSE AND EFFECT. 149 

since a change in the course of nature implies no 
contradiction. 1 Neither does it rest upon probable 
reasoning or arguments from experience, since "all 
these arguments" are founded on the principle of 
the uniformity of nature. 2 This principle is merely 
an assumption, a product of the imagination which 
arises from the constant conjunction of similar in- 
stances. 3 Consequently, "the foundation of all con- 
clusions from experience" is constant conjunction and 
custom. 4 Hence these two forms of the argument 
are ultimately one and the same. Constant or cus- 
tomary conjunction of resembling objects has such an 
influence upon the imagination, that on the appearance 
of one the mind passes on to the thought of the other ; 
or as otherwise put, resembling impressions and ideas 
that have been constantly conjoined introduce one 
another, so that the repetition of similar instances 
carries the mind beyond actual experience, and causes 
it to expect similar instances in the future under, 
similar conditions. Inference, therefore, is not an 
act of intuition,— of sense perception,— nor a process 
of demonstration, but is a transition of the imagina- 
tion produced by custom. "The foundation of all 
conclusions from experience" also, is ultimately cus- 
tom or habit. The nature of custom, however, the 
author professes, in each work, not to explain. It is 
a species of instinct, or "a principle of human nature, 
which is universally acknowledged, and which is well 
known by its effects." 5 But as in the case of the 
principles of association of ideas, no explanation of 

* Pp. 31, 33. 2 Ibid. 3 Pp. 30, 32, 33. < Pp. 30, 37, 39, 40. 
5 I, pp. 471, 475; IV, pp. 37, 40, 131. 



150 hume's treatise and inquiry. 

it can be given, except that furnished by experience 
and analogy. 1 

It is now manifest that, in his treatment of the par- 
ticular question of causation, Hume has answered— 
at least after his own fashion— the question in the 
Treatise for which the particular one was substituted, 
viz., how experience gives rise to the principle that 
"every thing whose existence has a beginning should 
also have a cause?" He had formerly shown that 
this principle is a conclusion from experience; 2 now 
he has explained the nature of inference, or experi- 
ential reasoning ; therefore, he has shown, how experi- 
ence gives rise to the principle that every event must 
have a cause. 3 He has answered this question in 
the Inquiry also. In the Inquiry he asked, what is 
the foundation of all conclusions from experience? 
Therefore he asked, at least by implication, what is 
the foundation of the principle that every event must 
have a cause?— that principle being a conclusion from 
experience. And to explain that "the foundation of 
all conclusions from experience" is constant conjunc- 
tion and custom, is equivalent to showing how experi- 
ence gives rise to the principle that every event must 
have a cause. This mode of handling the matter is 
certainly ingenious. Under the form of many ques- 
tions, Hume arranged the argument to suit his con- 
venience, and implicitly assumed one of the main 
points to be proved. 4 To this assumption, of course, 
he was fully entitled, according to the fundamental 
principles of his system of philosophy. And it may 

Wf. I, pp. 321, 330, 392, 393, 471; IV, p. 37. 

2 Of. p. 144, above. Wf. I, p. 389. 

*Cf. I, pp. 380, 381, 383, 385, 390; IV, pp. 24, 27, 30, 31. 



THE IDEA OF CAUSE AND EFFECT. 151 

be noted that, on discarding this assumption, viz., that 
all perceptions are distinct and separable, Hume's 
position, although bereft of one of its conspicuous 
supports, is, in its essential import, or with but slight 
modifications, perfectly valid. 

Logically, the next question for discussion is the 
third part of the particular question of causation, 
viz., the nature of belief. But as it seems advisable 
to devote a chapter to this topic, we pass on to the 
last general division, that is, necessary connection. 

III. The Idea of Necessary Connection.— In the 
fourteenth section of Part III of the Treatise, and in 
the seventh section of the Inquiry, Hume returns to 
the question which was left unanswered at the begin- 
ning of the discussion, and w T hich was supposed to be 
conversant with the chief element of the idea of cause 
and effect, viz., the question of necessary connection. 1 
But having answered, in the manner that he did, the 
first two questions— the general one, and the particular 
one,— he has practically answered the third, that of 
necessary connection. For if nothing is known about 
causation except what is derived from experience, and 
if the ultimate ground of experience is custom, or 
instinct, then there is no element of necessity, as com- 
monly understood, in the idea of cause and effect. 
As Hume asserts:- "The necessary connection betwixt 
causes and effects is the foundation of our inference 
from one to the other. The foundation of our in- 
ference is the transition arising from the accustomed 
union. These are, therefore, the same." Thus he 
arrives by a process of reasoning at a conclusion sim- 
ilar to the assumption with which lie had started out: 

1 I, p. 379. 2 1, p . 4go. 



152 hume's treatise and inquiry. 

"As all distinct ideas are separable from eacli other, 
and as the ideas of cause and effect are evidently dis- 
tinct, it will be easy for us to conceive any object to 
be non-existent this moment, and existent the next, 
without conjoining to it the distinct idea of a cause 
or productive principle." 1 So far as we know, there- 
fore, or. are capable of knowing, objects or events are 
related only by means of association and custom. 
Hence Hume, in explaining necessary connection, has 
really explained it away. Necessity exists only in 
the mind, not in objects. "Either we have no idea 
of necessity," he says, 2 "or necessity is nothing but 
that determination of the thought to pass from causes 
to effects, and from effects to causes, according to 
their experienced union." It might only remain now 
for Hume to show how the fiction of necessary con- 
nection has arisen. But as he has just examined ' ' one 
of the most sublime questions in philosophy," he 
thinks it may be advisable to give a fuller account of 
his doctrine. For that reason, he brings forward 
some additional arguments to show that the idea is 
invalid. The two topics will be treated separately. 
1. The idea of necessary connection is invalid. As 
usual, in testing the validity of any idea, Hume brings 
forward his "articles of inquisition," and demands 
from what impression the idea of necessary connec- 
tion is derived? 3 It is not derived by means of the 
senses, from the observation of objects, because the 
only relations perceivable among objects are contiguity 
and succession. 4 It is not derived by means of thought 

i I, p. 381; IV, p. 27. 2 1, p. 460; IV, p. 62. 

si, p. 450; IV, p. 52. * IUd. 



THE IDEA OF CAUSE AND EFFECT. 153 

or reasoning, because reason can produce no new idea. 1 
And it is not derived from a "supreme spirit" or the 
operations of "deity/' as the Cartesians held, for the 
doctrine of innate ideas has been rejected, and power 
is not discoverable in spirit any more than in body. 2 
These are the main arguments adduced, and thus far 
the reasoning, in both works, though different in form, 
is identical in import. 

In the Treatise, however, Hume incidentally ad- 
mitted that if the idea of power were once acquired, 
power might be attributed to "an unknown quality." 3 
This admission seems to have been seized upon by his 
opponents as a point of vantage, for an additional 
argument was introduced in the appendix to refute 
those who assert "that we feel an energy, or power, 
in our own mind," and then "transfer that quality 
to matter. " " But to convince us how fallacious this 
reasoning is," says Hume/ "we need only consider, 
that the will being here considered as a cause, has no 
more a discoverable connection with its effects, than 
any material cause has with its proper effect. So far 
from perceiving the connection betwixt an act of 
volition, and a motion of the body; it is allowed that 
no effect is more inexplicable than the powers and 
essences of thought and matter. Nor is the empire 
of the will over our mind more intelligible. ... In 
short, the actions of the mind are, in this respect, the 
same with those of matter. We perceive only their 
constant conjunction; nor can we ever reason beyond 

1 T, p. 452; IV, pp. 52, 53. 

2 I, pp. 454, 455; IV, pp. 58, 59, 60. » I, p. 455. 

4 I, ]>. 456; cf. p. 541 for a verbal contradiction of the last 

sentence. 



154 hume's treatise and inquiry. 

it. No internal impression has an apparent energy, 
more than external objects have." This argument 
was again br.ought forward in the Inquiry, and pre- 
sented with considerable fulness of detail. 1 Its im- 
portance was probably overlooked, or underestimated 
in the earlier work. This is one of the very few 
instances in which there is any development in the 
Inquiry, of Hume's doctrine. Otherwise the argu- 
ment has little significance, for it had been implied 
in the Treatise. 2 The conclusion of the reasoning in 
both books is exactly the same, viz., one never has an 
impression of power or necessary connection, and con- 
sequently cannot obtain a valid idea of it. 

2. How the Fiction of necessary connection arises. 
It is thought, however, that one has an idea of power, 
or of necessary connection between objects or events ; 
hence, the author, 's next task is to account for this 
fiction. Concerning the origin of the idea, the ex- 
planation of the two works is identical. 3 It is briefly 
as follows: One event is observed to follow another 
immediately; when this instance of two events in 
immediate succession has been repeated a number of 
times, the repetition, through custom, or instinct, pro- 
duces a new sentiment or feeling, an impression of 
reflection; and this impression of reflection gives 
rise to the idea of power or necessary connection. 
" Necessity, then," says Hume, 4 "is the effect of this 
observation, and is nothing but an internal impression 
of the mind, or a determination to carry our thoughts 
from one object to another." Thus the idea of power 
or necessary connection is a product of the imagina- 
tion. 

1 Pp. 54-57. 2 p. 455. 

s I, pp. 457, 458; IV, pp. 61, 62. *I, p. 459; cf. IV, p. 63. 



THE IDEA OF CAUSE AND EFFECT. 155 

In the Treatise/ the author expressed an apprehen- 
sion that although his "foregoing reasoning" appeared 
to him "the shortest and most decisive imaginable, ' ' 
yet "with the generality of readers' ' the bias of the 
mind to regard necessary connection as something 
objective would prevail, and give them a prejudice 
against his doctrine. This bias he explained in the 
following manner: 2 "It is a common observation, that 
the mind has a great propensity to spread itself on 
external objects, and to conjoin with them any internal 
impressions w r hich they occasion, and which always 
make their appearance at the same time that these 
objects discover themselves to the senses. . . . The 
same propensity is the reason, why we suppose neces- 
sity and power to lie in the objects we consider, not 
in our mind, that considers them." These remarks 
are omitted in the Inquiry. But the omission is not 
significant, since the same explanation of the bias of 
mind here referred to is implied in a foot-note, 3 and 
is again stated in The Natural History of Religion. 4 ' 

IV. Conclusion. Hume's account of necessary 
connection, particularly that in the Treatise, is by no 
means so simple as might appear from the above state- 
ment. The discussion abounds in repetitions, obscuri- 
ties, and even inconsistencies. Yet the inconsistencies 
are often verbal rather than real, arising from the use 
of terms, sometimes purposely, in a loose and popular 
sense. It is allowed, for instance, that there are 
powers and operations of nature; 5 also power or effi- 
cacy is spoken of as uniting causes and effects. 8 But 
Hume explains that, "in all these expressions, so ap- 
plied, we have really no distinct meaning, and make 

1 P. 4G1. ^ Ibid. »P. G4. <IV, p. 317. 5 P. 4G2. «P. 4 r,i;. 



156 hume's treatise and inquiry. 

use only of common words, without any clear and 
determinate ideas." 1 Again, the idea of power, of 
necessity, or of necessary connection is said to arise 
from a new impression, or determination, 2 from sim- 
ilar instances, or the observation of similar instances, 3 
from an internal impression, or impression of reflec- 
tion, 4 from a propensity, 5 from the repetition of re- 
lated objects, 6 from habit or custom, 7 and from imag- 
ination. 8 If Hume had enjoyed the opportunity of 
presenting his system of philosophy in the class room, 
or had experienced the necessity of defending it as he 
formulated it, he would have been more precise in his 
use of terms, and more consistent in his form of ex- 
pression. His various accounts of the derivation of 
the idea of necessary connection may be summarized 
briefly as follows: The terms efficacy, agency, power, 
force, energy, necessity, connection, and productive 
quality, "are all nearly synonymous." 9 Eepetition, 10 
custom, 11 similar instances, 12 constant conjunction, 13 * 
instinct, 14 or imagination 15 produce a determination 
of the mind, a propensity, habit, customary transition, 
or impression of reflection. This determination, 16 pro- 
pensity, 17 habit, 18 customary transition 19 — qualities of 
perceptions, 20 — or internal impression 21 is equivalent 
to power, necessity, or necessary connection. The idea 



iP. 457; cf. IV, p. 29 n. 




2 Pp. 450, 451, 463 




3 Pp. 457, 459. 




* P. 460. 


s Ibid. 


•P. 461. 




* P. 508. 


* P. 511. 


9 1, p. 451; IV, p. 51. 




ioi, pp. 450, 461. 




ii Pp. 460, 464, 511. 




12 P. 459. 


is P. 464. 


i4 P. 471. 




is Pp. 464, 511. 




is Pp. 451, 459, 460, 461, 


463. 




"P. 460. 


is Pp. 429, 508. 




is P. 461. 


™Ibid. 


2i Pp. 459, 460. 









THE IDEA OF CAUSE AND EFFECT. 157 

of power, of necessity, or of necessary connection is a 
copy of an internal impression, or impression of reflec- 
tion. 1 Consequently, the idea of power, of necessity, 
or of necessary connection arises immediately or di- 
rectly from a determination of the mind, propensity, 
habit, customary transition, internal impression, or 
the imagination; and mediately or indirectly from 
repetition of related objects, observation of similar 
instances, constant conjunction, custom, or instinct. 

§ 29. Misconceptions of Hume's Critics.— From the 
above examination of Hume's treatment of the idea 
of cause and effect, it is evident that the position of 
both works is substantially identical. 2 There are dif- 
ferences in the manner of statement, it is true, but 
.these do not seem to be significant. Some of Hume 's 
interpreters, however, put forward the claim that, 
with respect to certain aspects of the question, there 
are real and important differences in the Inquiry. 
The opinions of these writers, as well as a few mis- 
conceptions of others regarding Hume's view of 
causality call for some further consideration. 

Selby-Bigge 3 also asserts that, in the Inquiry, "the 
tiguity practically drops out altogether" in "the 
account of the origin, in particular, cases, of the idea 
of cause and effect"; and that "the account of causa- 
tion, ... is left hanging in the air when the sup- 
port of the theory of succession has been withdrawn.' ' 
There does not seem to be sufficient ground to warrant 
these statements. Hume, it is true, affirms that "all 

■ Pp. 454, 4G0, 4G3. 

2 Cf . Brede, Der Unterschi< d <L Lehren H. , p. 3!); riloidcrer, 
Empiriamua u. Bkepsis, p. 169 and n. 

3 Hume's Enquiries, pp. xiii, xv. 



158 hume's treatise and inquiry. 

arguments from experience are founded on the sim- 
ilarity, which we discover among natural objects, and 
by which we are induced to expect effects similar to 
those, which we have found to follow from such ob- 
jects." 1 In like manner he had expressed himself in 
the Treatise. 2 The passage just quoted, however, and 
several others in the Inquiry of a like import, do not 
mean that the relation of resemblance has now as- 
sumed the functions formerly exercised by contiguity 
and succession in explaining the origin, in particular 
cases, of the idea of cause and effect. On the con- 
trary, several statements clearly indicate that the 
relations of contiguity and succession play, respec- 
tively, the same r.ole here as in the earlier work. 
Thus Hume asserts: 3 "Suppose a person, though en- 
dowed with the strongest faculties of reason and re- 
flection, to be brought on a sudden into the world; 
he would, indeed, immediately observe a continual 
succession of objects, and one event following an- 
other; but he would not be able to discover anything 
farther. . . . Suppose again, that he has acquired 
more experience, and has lived so long in the world 
as to have observed similar, objects or events to be 
constantly conjoined together; what is the conse- 
quence of this experience? He immediately infers 
the existence of one object from the appearance of 
the other." Also, when speaking of the idea of 
necessary connection, he says: 4 "All events seem 
entirely loose and separate. One event follows an- 
other ; but we never can observe any tie between them. 
They seem conjoined, but never connected." And in 

iP. 31. 2 p. 391. 

3 Pp. 36, 37; cf. pp. 24, 30, 33. * p. 61. 



THE IDEA OF CAUSE AND EFFECT. 159 

a note in the edition of 1751 he made the decisive 
remark: 1 "A cause is different from a sign; as it 
implies precedency and contiguity in time and place, 
as well as constant conjunction. ' ' The fact that con- 
tiguity is omitted in the definitions of cause given in 
the Inquiry is not significant, since the meaning of 
the word is clearly implied. 2 

Selby-Bigge 3 also asserts that, in the Inquiry, "the 
distinction between causation as a philosophical and 
a natural relation is altogether dropped." This 
statement is not justified. In the Treatise, 4 Hume 
gave two definitions of cause, one as a philosophical 
relation, the other as a natural relation. In the In- 
quiry, 5 he gave two corresponding definitions. These 
are briefer than those in the Treatise, but they are 
similar in meaning. For reasons already given, 6 the 
author omitted in the later, work an explicit distinc- 
tion between natural and philosophical relations. As 
might be expected, therefore, in the definitions of 
cause, this distinction, although implied, is not form- 
ally expressed. In the section on "Liberty and 
Necessity," this same distinction is again implied. 
Hume asserts: 7 "Necessity may be defined two ways, 
conformably to the two definitions of cause, of which 
it makes an essential part. It consists either in the 
constant conjunction of like objects, or in the infer- 
ence of the understanding from one object to an- 
other." That is, necessity, like cause, may be re- 
ded cither as a philosophical, or as a natural 

1 IV, p. 64. 2iv, p. 63; of. p. 71). 

J Hume's Enq%Urie$ t [ntrocL <I\ 465. 

' l*. 63; <■[. Brede, Der UnterscMed d. Lehren If., p. 39. 

6 Pp. 80-83. i P. 79. 



160 hume's treatise and inquiry. 

relation. Selby-Bigge 's account of Hume's treat- 
ment of causation is somewhat obscure, no doubt 
owing to brevity of statement. Indeed it hardly 
appears to be perfectly consistent. For although he 
says that "contiguity practically drops out alto- 
gether" in the account of the origin, in particular 
cases, of the idea of cause and effect; he also says: 
"Contiguity, . . . drops out of the Enquiry as a 
philosophical relation, though it must be supposed to 
exert its influence as a natural relation." 1 It is suf- 
ficient to remark here that Selby-Bigge 's distinction 
between natural and philosophical relations does not 
exactly conform to that of Hume. Indeed the editor 
of Hume's Enquiries does not seem to be quite free 
from the bondage of that " relationism " which 
weighed like a nightmare on the mind of Green, and 
still vexes sore the souls of his readers. 

According to Peterson, 2 the explanatory definition 
of cause, inserted in edition K of the Inquiry— 1753- 
54— "is identical with the traditional doctrine" of 
causation. And Selby-Bigge 3 contends that this 
clause added "in italics can hardly be regarded as a 
paraphrase or equivalent of the main definition" in 
the Inquiry. It is usually unfortunate for critics 
to differ diametrically with their author in the inter- 
pretation of his language. In edition K of the In- 
quiry, after defining cause as a philosophical relation, 
Hume added the following sentence: 4 "Or, in other 
words, where, if the first object had not been, the 
second never had existed.' 9 Of course, it might seem 

1 Hume's Enquiries, pp. xv, xvi. 

2 Phil Rev., Vol. VII, p. 47. 

3 Hume's Enquiries, Introd. 4 P. 63. 



THE IDEA OF CAUSE AND EFFECT. 161 

to a casual observer as if this new definition were 
"identical with the traditional doctrine" of causa- 
tion, or at least as if it were not an "equivalent of 
the main definition in the Inquiry." But Hume re- 
garded it as being identical with his doctrine of 
causation ; it is his own definition of cause expressed 
"in other words." Furthermore, it may be noted 
that Hume fairly guarded himself from a mistaken 
interpretation like that of Peterson or of Selby-Bigge 
when he remarked, in a note on the succeeding sec- 
tion: 1 "If a cause be defined, that which produces 
any thing; it is easy to observe, that producing is 
synonymous to causing. In like manner, if a cause 
be defined, that by which anything exists; this is 
liable to the same objection. For what is meant by 
these words, by which? Had it been said, that a 
cause is that after which anything constantly exists; 
we should have understood the terms. For this is, 
indeed, all we know of the matter. And this con- 
stancy forms the very essence of necessity, nor have 
we any other idea of it." 

Brede 2 states that, in the Inquiry, there is a higher 
estimation of the worth of the causal inference than 
in the Treatise. On the other hand, Selby-Bigge 
rts: 3 "The distinction [between natural and phi- 
losophical relations] in the Treatise is indeed most 
bewildering, but, with its disappearance in the En- 
quiry, the relation of causation becomes more com- 
pletely subjective." While Peterson 4 affirms that, in 
the Treatise "the subjective aspect is made still more 

1 P. 78. *Der Lntcrschicd d. Lchrcn II., p. 30. 

8 Ihnnr's Enquiries, p. xvii; cf. p. xv. 
* Phil. AV,., Vol. VII, p. 45. 

11 



162 hume's treatise and inquiry. 

prominent" than in the Inquiry. The correctness or 
incorrectness of these conflicting assertions can be 
shown only by appealing to the author himself. No 
doubt it is tedious to resort continually to quotations. 
But there is no other method of dealing with the 
question under discussion. The subject will be dealt 
with as briefly as possible. In the Treatise Hume 
asserts: 1 "We have already taken notice of certain 
relations, which make us pass from one object to 
another, even though there be no reason to determine 
us to that transition; and this we may establish for 
a general rule, that wherever the mind constantly and 
uniformly makes a transition without any reason, it 
is influenced by these relations." The relations are 
resemblance, contiguity, and cause and effect. 2 But 
cause and effect arises from resemblance and constant 
conjunction, that is, from resemblance, contiguity, 
and custom. And the causal inference is produced, 
not by the relations of resemblance and contiguity 
simply, but by the repetition of these relations, that 
is, by custom. Hence Hume says later, "all reason- 
ing concerning matters of fact arises only from cus- 
tom." 3 In the Inquiry he states: 4 "Though we 
should conclude, ... as in the foregoing section, 
that, in all reasoning from experience, there is a step 
taken by the mind, which is not supported by any 
argument or process of the understanding, there is 
no danger, that these reasonings, . . . will ever be 
affected by such a discovery. If the mind is not en- 
gaged by argument to make this step, it must be in- 
duced by some other principle of equal weight and 

i P. 392. 2 p. 393. 

3 P. 487; cf. pp. 444, 475. 4 P. 36. 



THE IDEA OF CAUSE AND EFFECT. 163 

authority." This principle is "custom or habit," a 
principle which determines one to draw the causal 
inference when one has lived "so long in the world 
as to have observed similar objects or events to be 
constantly conjoined together." 1 

It is now necessary to discover the nature of cus- 
tom, to learn if it is of "equal weight and authority" 
with reason. In the Treatise, the author does not 
give any satisfactory account of this principle. In 
a general way he regards it as the repetition of a 
number of particular instances, 2 but more specifically, 
as a quality of mind or mode of activity resulting 
from the repetition of the same experience. 3 He 
sometimes uses reasoning synonymously with custom, 
speaking of it as "a wonderful and unintelligible 
instinct" in the soul, a principle of nature that is 
common to man and beast. 4 He even holds custom 
to be more trustworthy than reason proper, or the 
understanding. ' ' By the same rule, ' ' says Hume, 5 as 
the skeptic "continues to reason and believe, . . . 
he must assent to the principle concerning the exist- 
ence of body, . . . Nature has not left this to his 
choice, and has doubtless esteemed it an affair of too 
great importance to be trusted to our uncertain 
reasonings and speculations." Belief in "the exist- 
ence of body" arises from custom and imagination. 
In Part IV, it is true, the author— in a criticism of 
the "faculty, which judges"— professes to reduce, by 
"the rules of logic," probable reasoning, that is, the 
causal inference, to "a total extinction of belief and 

1 P. 37. * Pp. 458, 459. 

3 P. 403. * Pp. 470, 471; cf. p. 403. 

6 P. 478. s Pp. 487, 488. 



164 hume's treatise and inquiry. 

evidence." 1 But he immediately adds: "Should it 
here be asked me, whether I sincerely assent to this 
argument, . . . and whether I be really one of 
those skeptics, who hold that all is uncertain, . . . 
I should reply, . . . Nature by an absolute and un- 
controllable necessity has determined us to judge as 
well as to breathe and feel; nor can we any more 
forbear viewing certain objects in a stronger and 
fuller light, upon account of their customary connec- 
tion with a present impression, than we can hinder 
ourselves from thinking as long as we are awake, or 
seeing the surrounding bodies, when we turn our eyes 
towards them in broad sunshine." Yet, in another 
place, Hume admits that custom is at times the ground 
of illusion, and "may lead us into some false com- 
parison of ideas." 2 Thus in the Treatise, belief in 
the existence of body is "an affair of too great im- 
portance" to be entrusted by nature to "our uncer- 
tain reasonings and speculations"; it is entrusted to 
custom and imagination. And the causal inference 
is determined through custom or instinct with an ab- 
solute and uncontrollable necessity; yet custom is 
sometimes false or illusive. The case is exactly sim- 
ilar in the Inquiry. For instance, Hume asserts: 3 
"I shall add, for a further confirmation of the fore- 
going theory, that, as this operation of the mind, by 
which we infer like effects fr.om like causes, and vice 
versa, is so essential to the subsistence of all human 
creatures, it is not probable, that it could be trusted 
to the fallacious deductions of our reason, ... It 
is more conformable to the ordinary wisdom of nature 

i P. 474. * P. 415; cf. pp. 444, 547, 548. 

» P. 47; cf. pp. 124, 127. 



THE IDEA OF CAUSE AND EFFECT. 165 

to secure so necessary an act of the mind, by some 
instinct or mechanical tendency [that is, custom], 
which may be infallible in its operations. ' ' But in 
section xii he admits: 1 "We have no argument to 
convince us, that objects, which have, in our experi- 
ence, been frequently conjoined, will likewise, in 
other instances, be conjoined in the same manner; 
and that nothing leads us to this inference but cus- 
tom or a certain instinct of our nature; w r hich it is 
indeed difficult to resist, but which, like other in- 
stincts, may be fallacious and deceitful. While the 
skeptic insists upon these topics, he show r s his force, 
or rather, indeed, his own and our weakness; and 
seems,for the time at least, to destroy all assurance 
and conviction. ' ' True, in the Inquiry, Hume does 
not subject the "faculty, w r hich judges/' to the crit- 
ical examination that he did in the Treatise. Never- 
theless, as he once wrote Strahan, 2 concerning the 
essays on suicide and immortality: "I suppressed 
these Essays, not because they could give any offence, 
but because, I thought, they could neither give pleas- 
ure nor instruction, ' ' so he remarks now, regarding 
the reasoning of the skeptic: "These arguments might 
be displayed at greater length if any durable good or 
benefit to society could ever be expected to result 
from thein." 3 This observation evidently implies 
that his position on this topic also remains unchanged. 
It has often been asserted, on the one hand, that 
Hume denied the possibility of a necessary connection 
between causes and effects, and on the other, that he 
denied only the possibility of a knowledge of such 

" Pp. 130, 131; cf. I, pp. 547, 548; IV, p. 132. 

2 Hill, Letters of D. U. } p. 233. 3 P. 131. 



166 hume's treatise and inquiry. 

connection. Thus Knight 1 declares that Hume's 
theory of causation "positively affirms that there is 
no power within the antecedent adequate to produce 
the consequent, that the notion of such causal power 
is a fiction of the imagination." And Biehl 2 states 
that Hume never denied the existence of active prin- 
ciples in nature, but only their knowableness and 
conceivability. While each position may contain an 
element of truth, the latter is the more correct; it is 
conformable with Hume's practice, the former is the 
more consistent with his theory. Hume's language 
frequently implies the existence of external objects 
corresponding to impressions and ideas. Occasionally, 
he admits such existences. In the Treatise, he says: 3 
1 ' I am, indeed, ready to allow, that there may be sev- 
eral qualities both in material and immaterial objects, 
with which we are utterly unacquainted." And in 
the Inquiry, 4 he acknowledges "a kind of pre-estab- 
lished harmony between the course of nature and the 
succession of our ideas," although the "powers and 
forces" by which the course of nature is governed ar.e 
"wholly unknown to us." Hence, he does not mean 
to deny the existence of an external world endowed 
with various powers and forces, but only the possi- 
bility of knowing it. The rationalists and intuition- 
alists maintain, of course, that he overshoots the mark 
when he asserts, as he repeatedly does, that the idea 

1 Hume, p. 159; cf. Brougham, Lives of Men of Letters in the 
Time of George III, p. 172. Koenig, Die Entwiclcelung d. 
Causalproblems, I, p. 216 and n. 

2 Der philosophische Kriticismus, I, p. 129; cf. Burton, Life, 
I, p. 81; von Kirchmann, TJnter suckling in Betreff d. m. Ver- 
standes, p. 178. 

3 P. 462; cf. p. 477; II, p. 183. Pp. 46, 71. 



THE IDEA OF CAUSE AND EFFECT. 167 

of necessary connection among external objects is a 
fiction. For. to assert that this idea is fictitious and 
false is the same as to imply that there is not any 
necessary connection among objects in the external 
world. It should be observed, however, that the idea 
which Hume affirmed to be false was the rationalistic 
idea of causality. And in this respect, it will now be 
generally conceded that he was correct. Neverthe- 
less, had he contented himself with stating that such 
necessary connection, provided it exists, is unknown, 
the position would have been quite satisfactory to the 
empiricists, as well as perfectly consistent with his 
own principles. 

Finally, there are some writers 1 who insist that 
Hume 's theory of causation is the same, or practically 
the same as that of Kant. The truth of this state- 
ment depends upon the manner in which it is inter- 
preted. With Hume, as with Kant, the idea of cause 
and effect is subjective, and is not valid when applied 
to suprasensible things; to this extent both agree. 
According to Hume, however, the idea is empirically 
derived, by means of the imagination, from repetition, 
custom, or instinct, and in a similar manner is ap- 
plicable to perceptions; while according to Kant, the 
idea is a transcendental concept of the understanding, 
and is a priori valid when applied within the realm 
of phenomena. "With the former, therefore, the idea 
is equivalent to the invariable succession of antecedent, 
and consequent; with the latter, it contains an element 
of necessity over and above invariable succession. 
True, according to Hume, the idea of cause and effeel 

1 Of. Etiehl, Der phiJosojjhischc Kriticismus, I, p. 139; Simon, 
Berkeley's Principles of Unman Knowledge, pp. 203, 20G; 
Webb, Vi II of Jsis, p. 94; Stirling, Mind, Vol. X, p. 71. 



168 hume's treatise and inquiry. 

contains, after a manner, an element of necessity also. 
But the necessity spoken of in this case is that which 
arises from imagination and custom, from an instinct 
which is the great guide of human life, but which, 
like any other instinct, may be fallacious and deceit- 
ful. This subjective necessity of imagination and 
custom is fundamentally different from that a priori 
necessity of the understanding for which Kant per- 
sistently contended. 

§ 30. Conclusion.— The main points in the chapter 
may now be brought together. There are two prom- 
inent elements in Hume's treatment of the idea of 
cause and effect; one logical or epistemological, the 
other psychological. The former deals with the 
ground of the transition or causal inference; the 
latter explains the genesis of the idea of necessary 
connection. 

1. The causal inference is not a conclusion of the 
understanding, but an activity of the imagination. 
It is not a logical inference, but a psychological 
process. It is not a product of reason, but of cus- 
tom. It arises on the observation of a number of 
similar instances constantly conjoined, and differs 
from a mere idea of imagination in having greater 
force, vivacity, or liveliness, that is, belief. Al- 
though the conclusion is not a valid inference log- 
ically, yet psychologically it is a necessary one. It is 
even spoken of as being superior to the "fallacious 
deductions" of reason. 1 At the same time, however, 
not only does there exist a conflict between the imag- 
ination and instinct, on the one hand, and the under- 
standing, or "the general and more established prop- 

il, p. 478; IV, p. 47. 



THE IDEA OF CAUSE AND EFFECT. 169 

er.ties of the imagination, ' n on the other, but each of 
these faculties alone subverts or contradicts itself. 2 
The causal conclusion rests upon precisely the same 
basis in both works. Although the inference, or 
transition cannot be theoretically justified; yet prac- 
tically, it is indubitable, and is sufficient for all the 
purposes of life. 

2. The idea of necessary connection between causes 
and effects arises in the mind at the same time as the 
causal inference, and in the same manner, viz., from 
experience, through imagination and custom. The 
genesis of the idea has three stages, two of which may 
be called objective, and one subjective: (1) The mind 
observes a number of similar instances constantly 
conjoined; (2) as the result of this observation, a new 
feeling, determination, or internal impression arises, 
the impression of reflection of which the idea of neces- 
sary connection is a copy; (3) the idea of necessary 
connection, which at first is wholly subjective, is 
gradually applied to external objects through a 
quality of the imagination, and in this way arises the 
idea of necessary connection between objects or events. 
Consequently, the idea of cause and effect is valid as 
a copy of a subjective feeling, and is applicable to 
objects in the sense of invariable succession of ante- 
cedent and consequent; but as an idea of necessary 
connection between objects or events, it is a mere 
fiction. The genesis of the idea explains its nature 
and validity. On all these points the position of the 
Inquiry is the same as that of the Treatise. 

In the history of speculative thought, the paradoxes 

1 I, p. 547. 2 I, pp. 505, 511, 547; IV, pp. 125, 127, 131. 



170 hume's treatise and inquiry. 

of one age often become the orthodoxy of the next, 
and in turn become the absurdities of the succeeding 
age. Such has been true of the idea of cause and 
effect. Invariable succession of antecedent and con- 
sequent, the striking paradox of Hume's day, became 
in a later time the commonly accepted view of causa- 
tion, and has now in turn given place to a juster 
conception, that of the equivalence of cause and effect. 
But while thought moves in cycles, these at most are 
only corresponding, never identical. The empiricist's 
criticism of causality has been made once for all. As 
Luther burst the bonds of scholasticism, Hume rent 
for ever the veil of rationalism. The philosopher, 
however, was more successful at demolishing old 
temples, than at erecting new ones. While the 
foundation which he first laid still remains, the 
Humian structure, never stable, has already crumbled 
with its own weight. It is beyond the scope of this 
work, of course, to give a derivation of the idea of 
cause and effect. Suffice it to say, that this idea is a 
product of experience. Its origin and history are to 
be sought in the life of the race. True, it passes 
through a series of corresponding stages in the life of 
each normal individual. Its dawn is unfolded in the 
conscious activity of the child. The essential element 
at this stage is producing power. The element of 
necessary connection does not arise until much later, 
sometimes indeed does not appear at all. The early 
age at which Hume wrote the Treatise is possibly a 
partial explanation why he insisted so strongly upon 
his principle that events seemed "conjoined" but not 
"connected," that it is easy "to conceive any object 
to be non-existent this moment, and existent the 



THE IDEA OF CAUSE AND EFFECT. 171 

next," without attaching to it the idea of "a cause 
or productive principle." The idea of equality be- 
tween cause and effect may arise either before, or 
after that of necessary connection, according to the 
character, of the person's environment. But the idea 
of causation, in any, and every stage of its develop- 
ment, is merely a generalization, conscious or uncon- 
scious, from the totality of experience. 1 

i Of. Schurman, Phil. Rev., Vol. VIII, p. 457-463. 



CHAPTER VIII. 



BELIEF. 



§ 31. Belief of Impressions. —Hume recognized two 
systems of knowledge, the counterpart of two worlds : 
one the system of impressions, corresponding to the 
world of sense and memory; the other the system of 
ideas, corresponding to the world of judgment, or of 
reason and imagination. 1 His distinctive treatment 
of belief occurs in the discussion on the particular 
question of causation. Naturally, therefore, his prob- 
lem is to explain belief of ideas, or more specifically, 
belief of the inferred idea in reasoning concerning 
matters of fact. Incidentally, however, he made an 
occasional reference, both in this and in other parts 
of the Treatise, to belief of impressions. 

Hume's doctrine concerning belief of impressions 
has been much misunderstood. Brede 2 asserts that 
Hume never calls the liveliness of impressions belief, 
only that of ideas. And Green 3 calls attention to 
what he takes to be an "inconsistency" in Hume's 
use of the word belief. "At the end of sec. 5 (Part 
III)," he says, "the term is extended to ' impressions 
of the senses and memory. ' . . . But in the following 
section the characteristic of belief is placed in the 
derived liveliness of an idea as distinct from the im- 

il, pp. 407, 408. 

2 Der Unterschied d. Lehren E., pp. 7, 50. 
8 1, p. 279 n.; cf. Zimels, David Humes Lehren vom Glaulen, 
pp. 10-12. 

172 



BELIEF. 173 

mediate liveliness of an impression." Neither of 
these views is quite correct. Hume's treatment of 
belief is certainly not clear, but on this point it is not 
necessarily inconsistent. To place the characteristic 
of belief, when dealing with " reasonings from causa- 
tion," in the derived "force and vivacity" 1 of an 
idea does not preclude the author, from attributing 
belief to impressions also. It is not surprising, there- 
fore, that he occasionally speaks of it in this latter 
sense, and ascribes to it a higher worth, or greater 
degree of assurance, than he does to belief of reason- 
ing concerning matters of fact. For, instance, he as- 
serts: 2 "The belief or assent, which always attends 
the memory and senses, is nothing but the vivacity of 
those perceptions they present." Also, 3 "Impres- 
sions always actuate the soul, and that in the highest 
degree; . . . Though an idle fiction has no efficacy, 
yet we find by experience, that the ideas of those 
objects, which w r e believe either are or will be existent, 
produce in a lesser degree the same effect with those 
impressions, which are immediately present to the 
senses and perception." And again, 4 "We may well 
ask, What causes induce us to believe in the existence 
of body? but it is in vain to ask, Whether there be 
body or not? That is a point, which we must lake 
for granted in all our reasonings." 

In the Inquiry, Hume refers only incidentally to 
belief of impressions; but he implies the same view 
as that in the Treatise. "Sensible objects," he says, 5 
"have always a greater, influence on the fancy than 

1 I. pp. 385, 39G; IV, p. 41. 2 P. 387. 

■ P. H7. #P. 478; cf. pp. 388, 448, 449. 

• P. 44. 



174 hume's treatise and inquiry. 

any other; and this influence they readily convey to 
those ideas, to which they are related, and which they 
resemble." Also in section xii he states: 1 "It seems 
evident, that men are carried, by a natural impulse 
or prepossession, to repose faith in their senses ; , . . 
Even the animal creation are governed by a like 
opinion, and preserve this belief of external objects 
[impressions], in all their thoughts, designs, and 
actions. ' ' 

§ 32. Belief of Ideas,— -It is to the explanation of 
belief of ideas, or rather of the inferred idea in ex- 
periential reasoning, that Hume particularly ad- 
dresses himself; for he includes belief, in this sense, 
in the problem of causation. In the Treatise he asks : 2 
"Wherein consists the difference betwixt believing 
and disbelieving any proposition ? ' ' And he replies : 
' ' The answer is easy with regard to propositions, that 
are proved by intuition or demonstration. In that 
case, the person, who asserts, not only conceives the 
ideas according to the proposition, but is necessarily 
determined to conceive them in that particular man- 
ner, . . . "Whatever is absur.d is unintelligible; nor 
is it possible for the imagination to conceive any thing 
contrary to a demonstration." In the Inquiry, he 
does not deal with intuitive or demonstrative proposi- 
tions,— probably because the answer was easy, and for 
the sake of brevity,— but only with belief concerning 
probable reasoning. To explain this belief is a special 
aim in both works. 

I. The Exposition of the Treatise. In the earlier 
work Hume asserts: 3 "The idea of an object is an 
essential part of the belief of it, but not the whole." 

i P. 124. 2 p. 395. 3 p. 394. 



BELIEF. 175 

Wherein then, it may be asked, does belief consist? 
An idea can be altered in any one of three ways: 
(1) A new element may be added to it; (2) the com- 
position of its parts may be varied; or (3) the manner 
of conception may be changed. Now belief of an 
idea, according to Hume, does not consist in any 
element, or part of a perception added to it, nor. in 
the order or composition of its parts. Consequently, 
it consists* only in "the manner" in which the idea is 
conceived. 1 "An opinion, therefore, or belief may be 
most accurately defined, a lively idea related to or 

CIATED WITH A PRESENT IMPRESSION." 2 Briefly 

stated then, Hume's position is this: In reasoning 
concerning matters of fact, an idea believed differs 
from an idea imagined merely in being more forcible, 
vivid, steady, lively, etc. And belief may be regarded 
equally, either as the force and vivacity of an idea, 
or as an idea in its force and vivacity; since it is, 
strictly speaking, neither the effect nor the cause of 
the force and vivacity, but the force and vivacity 
itself. 3 

II. The Exposition of the Appendix. In order to 
make his former reasoning more convincing and to 
guard against misconception, Hume discussed the sub- 
ject of belief somewhat further in the appendix. 
Here he made a few statements, however, which seem 
not only inconsistent in themselves, but also incom- 
patible with his former position. An apparent con- 
tradiction may first be disposed of. He affirms, as 
usual, that belief consists in some sentiment or feel- 
ing, which is not "distinguishable from the concep- 

1 P. 305. 2 P. 396. 

3 Of, pp. :vn\, 307 n., 300, 402, 405, 410. 



176 hume's treatise of human nature. 

tion." 1 Yet he admits that, in a certain ease of 
belief, viz., when the mind passes "from doubt and 
agitation to tranquility and repose, " there is "a feel- 
ing distinct and separate from the conception." 2 The 
latter statement is not, in reality, inconsistent with 
the former ; since feeling, in this particular instance, 
is an attendant on belief, though not an essential 
part of it, and is distinct and separate from belief 
as well as from the conception. 

A further remark raises a greater difficulty. In 
the Treatise, when explaining his view of belief, 
Hume said: 3 "When you would any way vary the 
idea of a particular object, you can only increase or 
diminish its force and vivacity.' ' In the appendix, 
he acknowledges that this statement is incorrect, and 
declares: 4 "I believe there are other differences 
among ideas, which cannot properly be comprehended 
under these terms. Had I said, that two ideas of 
the same object can only be different by their different 
feeling, I should have been nearer the truth.' ' No 
doubt had he said so, he would have been nearer the 
truth. For whatever feeling may mean, the author 
implies that it is something other, than degree of force 
and vivacity. Hume, however, does not explain the 
meaning of feeling. On the contrary, he confesses 
that "it is impossible to explain perfectly this feeling 
or manner of conception." 5 He still contends that 
belief differs from fiction only in "the manner of its 
being conceived." But he adds: 6 "When I would 
explain this manner, I scarce find any word that fully 
answers the case, but am obliged to have recourse to 

1 1, p. 556. 2 i 3 p . 557. s p. 396; cf. p. 397. 

* P. 560. s p. 398. 6 p. 397. 



BELIEF. 177 

every one's feeling, in order, to give him a perfect 
notion of this operation of the mind. An idea as- 
sented to feels different from a fictitious idea, . . . 
And this different feeling I endeavor to explain by 
calling it a superior force, or vivacity, or solidity, or 
firmness, or steadiness." Finally, he sums up the 
matter as follows: 1 "Thus upon a general view of 
the subject, there appear to be two questions of im- 
portance, which we may venture to recommend to the 
consideration of philosophers, Whether there be any 
thing to distinguish belief from the simple conception 
beside the feeling or sentiment? And, Whether this 
feeling be any thing but a firmer conception, or a 
faster hold, that we take of the object?" Both these 
questions, as indeed their forms imply, are answered 
in the negative. 

Now the question arises, what is Hume's doctrine 
of belief in the appendix? At first sight, it seems 
to be different from that in the Treatise ; but to what 
extent it may be different is by no means evident. 
The treatment in the earlier work possessed two prom- 
inent characteristics: (1) Hume repeatedly professed 
to be able to explain fully the whole matter; (2) his 
explanation was generally to the effect that, belief 
consists in the degree of "force and vivacity" of an 
idea, arising from its relation to a present impression. 
Now he states: (1) Belief is nothing but a peculiar 
feeling, or. manner of conception; (2) he is unable to 
explain perfectly the nature of this feeling. It might 
be thought, therefore, that his view of belief is en- 
tirely changed. Such, however, is not the case. In 
the Treatise, Hume maintained that the only differ- 

1 P. 557. 
12 



178 hume's treatise and inquiry. 

ence between impressions and ideas, or between two 
ideas of the same impression, is a difference of degree, 
and, in general, he thought that this difference of 
degree could be adequately expressed by the phrase 
" force and vivacity." 1 He still holds to the former, 
statement, but he has abandoned the latter. A deeper 
psychological insight has enabled him to perceive that 
there are differences of degree between impressions 
and ideas, or between two ideas of the same impres- 
sion, other than those that can be expressed by the 
words force and vivacity. There is a difference of 
firmness, steadiness, faster hold, etc., which is not 
properly included under the former term. All these 
differences may be covered by the word feeling; but 
feeling does not indicate that wherein the differences 
consist. Consequently, with the attainment of this 
juster view, Hume changes somewhat the account of 
his doctrine. He explains that the differentia of be- 
lief is not degree of force and vivacity. The context 
shows, however, that by this statement he only means, 
that degree of force and vivacity is not always the 
differentia of belief; he implies that sometimes it is. 2 
He now perceives clearly, what he does not seem to 
have fully realized, when writing the Treatise, that 
belief, psychologically, is not always the same thing. 
Feeling is an expansive term. Hence, in the ap- 
pendix, he asserts that the differentia of belief is 
feeling. He acknowledges that he cannot define this 
feeling. And when he endeavors to describe it he 
calls it "a superior force, or vivacity, or solidity, or 
firmness, or steadiness"; 3 a "firmer conception, or a 

i I, pp. 314, 327, 375, 396, 397, 403, 417. 

2 1, pp. 398, 556, 557. 3 I, p. 398. . , 



BELIEF. 179 

faster hold, that ice take of the object." 1 Farther he 
did not carry his analysis of the problem. 

It is now obvious that the position of the appendix 
differs but little from that of the Treatise. It differs 
even less, however, than has thus far been represented. 
Two remarks will make this clear. (1) It is not at 
all improbable that interpreters have attached too 
much importance to the use of the term feeling in 
the appendix. In many instances, as for example, 
when it is said that "an idea assented to feels dif- 
ferent from a fictitious idea," Hume may mean 
simply that the idea is perceived differently, or is 
felt to be different. (2) Although in the earlier 
work, the author generally seemed to be fully con- 
vinced that belief could be adequately explained as a 
difference in degree of force and vivacity, yet at times 
he was not so positive. In the section, ' ' Of the Causes 
of Belief/ 7 he acknowledged that there was "a little 
ambiguity" in the words "strong and lively"; 2 and 
repeatedly he used a variety of terms corresponding 
with those which he employed later in the appendix. 
Thus he described belief as "a strong and steady con- 
ception of any idea"; 3 as "firmness or solidity" of 
ideas; 4 as "a more vivid and intense conception" of 
an idea; 5 and as "some sensation or peculiar manner 
of conception." He even designated it as feeling. 
"It is not solely in poetry and music," he declared, 7 
11 we must follow our taste and sentiment, but like- 
wise in philosophy. When I am convinced of any 
principle, it is only an idea, which strikes more 



1 I. p. 557. 


■ P. 405. 


3 P. 397 n. 


• P. 406. 


* P. 418. 




6 P. 475. 


■ P. 403. 





180 hume's treatise and inquiry. 

strongly upon me. When I give the preference to 
one set of arguments above another, I do nothing but 
decide from my feeling concerning the superiority of 
their influence." It seems, therefore, that the doc- 
trine of belief, in the appendix, is substantially the 
same as that in the Treatise. An examination of the 
account in the Inquiry tends to confirm this con- 
clusion. 

III. The Exposition of the Inquiry. The doctrine 
of belief in the Inquiry is exactly the same as that in 
the appendix. After asserting, as the conclusion of 
the whole matter, concerning experiential reasoning, 
that "all belief of matter of fact or real existence is 
derived merely from some object, present to the mem- 
ory or senses, and a customary conjunction between 
that and some other object" ; Hume acknowledges that 
his further researches into "the nature of this belief, 
and of the customary conjunction," may, by the 
reader, who is not interested in abstract speculations, 
be neglected, without detriment to the understanding 
of "the following inquiries." 1 Because of this state- 
ment,— and some others to be examined presently,— 
Brede 2 affirms that, in the Inquiry, not only is there 
assigned to belief a subordinate significance, but the 
concept of it is positively changed. In these two re- 
spects, Zimels 3 agrees with Brede, and maintains fur- 
ther that all the essential modifications of the doctrine 
of the Inquiry appear, in the treatment in the ap- 
pendix. Several other writers hold the same opinion, 
on this question, as Brede or Zimels. 4 

1 P. 40. 2 Der UnterscMed d, Lelxren H., pp. 31, 50. 

3 David Humes Lehre vom Glauben, pp. 5, 6, 71. 
* Cf. Stephen, Hist, of English Thought, I, p. 44 n. 



BELIEF. 181 

Ziniels is the best, as well as the most recent ex- 
ponent of this view. His whole Dissertation is an 
argument to show, that Hume, in his exposition in 
the Treatise, met with difficulties and even contradic- 
tions which obliged him to change gradually, although 
unconsciously, his form of statement; that on review- 
ing the subject, in order to evade these difficulties and 
remove the contradictions, he modified his doctrine, 
in the appendix, to such an extent, that it not only 
conflicts with that of the Treatise, but contradicts one 
of the fundamental principles of his system; natu- 
rally, therefore, since his whole treatment was un- 
satisfactory, and he felt himself unable to master the 
problem, he cut short the exposition, in the Inquiry, 
and, passing over the chief difficulties, endeavored to 
make his view of belief consistent, both in itself, and 
with the general principles of his philosophy. Zini- 
els' argument is plausible as well as ingenious. It is 
more than plausible. It contains an element of valid- 
ity ; but is not quite conclusive. 

The treatment of belief, in the Inquiry, is exceed- 
ingly brief, and also comparatively unimportant. It 
is brief, not because of difficulties realized by the 
author, but for quite other reasons: (1) Hume omitted 
a specific account of belief of impressions, and of ideas 
in intuitive and demonstrative reasoning, although he 
maintained that with regard to them there was no 
difficulty whatever; (2) he aimed at brevity and sim- 
plicity on general principles; they were part of his 
avowed method; and (3) he was writing for a dif- 
ferent class of readers. The treatment is, compara- 
tively speaking, unimportant because: (1) As Hume's 
rial problem was to explain belief of the inferred 



182 hume's treatise and inquiry. 

idea in reasoning on causation, incidental treatment 
of the subject, in connection with the causal conclu- 
sion, was sufficient for his purpose; and (2) having 
dealt with this question in the appendix, as well as 
in the Treatise, he had then nothing further to add, 
and also nothing to take away. 

It is said, however, that there are contradictions in 
the former account, and that these demand explana- 
tion. Here are some of those commonly pointed out. 
(1) In the Treatise, Hume asserted: 1 "The vivacity 
produced by the fancy is in many cases greater than 
that which arises from custom and experience. We 
are hurried away by the lively imagination of our 
author or companion ; and even he himself is often a 
victim to his own fire and genius.' ' This statement 
does not imply a contradiction in the philosophy of 
human nature; it simply expresses a fact observable 
in every-day life. An untruth, if well told, is often 
believed; even the narrator may in time deceive 
himself, as do habitual story-tellers, "who by the 
frequent repetition of their lies, come at last to be- 
lieve and remember them, as realities." 2 1(2) Again, 
when speaking of the effect of general rules, Hume 
affirmed in the appendix: 3 "A like reflection on gen- 
eral rules keeps us from augmenting our belief upon 
every increase of the force and vivacity of our ideas. 
Where an opinion admits of no doubt, or opposite 
probability, we attribute to it a full conviction; 
though the want of resemblance, or contiguity, may 
render its force inferior to that of other opinions." 
The difficulty which, at first sight, appears here van- 
ishes on the slightest reflection. Hume was not a 

i P. 420. 2 i, p . 387. 3 i } p . 422. 



BELIEF. 183 

modern, or experimental psychologist. He adopted 
the static view of mind, and also the atomistic. Yet 
he knew nothing of structural psychology, as distinct 
from functional. His analysis was always good, as 
far as it went; but often it did not go very far. 
Such was the case in the present instance. Hume 
was dealing with an exceedingly complex group of 
mental processes. When dealing with groups of this 
character, he divided each into two main parts, the 
present impression, and the related idea. He did not 
observe, however, that these two constituents are still 
complex ; and failing in this respect, he also failed to 
note the existence of many of their less prominent 
elements. Besides these two chief constituents, he 
recognized certain relations subsisting between them, 
viz., causation, resemblance, and contiguity. But 
this impression, the idea, and the relations, as Hume 
regarded them, do not constitute the whole of a con- 
scious content, They do not include all of that 
"fringe of relations' ' in w r hich a conscious content 
commonly has its setting. They are part of the 
totality of experience, as their objects are part of the 
real world. As such they are related by the same, 
or by other relations to other impressions and ideas. 
On account of these latter impressions, ideas, or rela- 
tions, which Hume did not recognize, the idea which 
he did recognize may be attended by a feeling of 
solidity, firmness, steadiness, faster, hold, or force 
and vivacity, corresponding with the specific char- 
acter of the mental content. Hume, in the Treatise, 
appendix, and Inquiry, recognized the more prom- 
inent of these emotional elements, and designated 
them according to their several characteristics. All 



184 hume's treatise and inquiry. 

were included, finally, under the term feeling, the 
natur.e of which varied for each particular experience. 
General rules are based on causation, resemblance, 
and contiguity, and arise through repetition or cus- 
tom and generalization. They may produce belief as 
a feeling of firmness, steadiness, or faster hold, when 
the idea has comparatively little force and vivacity; 
or vice versa, they may inhibit belief, as when a very 
vivid idea, or, even a hallucination, is held to be un- 
real by the person who experiences it. 

Further, it is said that the doctrine of the Inquiry 
is inconsistent with that of the Treatise. The only 
grounds for this assertion are Hume's admission, in 
the appendix, 1 that " there are other differences among 
ideas, which cannot properly be comprehended" 
under the expression " force and vivacity," and his 
adoption, in the later writings, of the term feeling 
to express the exact nature of belief. But it has 
already been pointed out 2 that the author recognized, 
in the earlier work, an ambiguity in the phrase * ' force 
and vivacity," and that he used feeling, as well as 
all the other, distinctive terms in the appendix, to 
explain belief. It may now be shown that all the 
expressions employed for this purpose in the later 
work were also used in the earlier. In the Inquiry, 
Hume states: 3 "The difference between fiction and 
belief lies in some sentiment or feeling, which is an- 
nexed to the latter, not to the former, and which 
depends not on the will, nor can be commanded at 
pleasure. ... In this consists the whole nature of 
belief." In the Treatise, 4 he said, that "all probable 

1 1, p. 560. 2 p. 179. 

3 P. 41. * P. 403. 



BELIEF. 185 

reasoning is nothing but a species of sensation"; that 
in philosophy, as well as in poetry and music, "we 
must follow our taste and sentiment"; and that "the 
preference, ' ' or belief, of ' l one set of arguments above 
another" is only decided by one's "feeling." True, 
in the Inquiry, he admits: 1 "were we to attempt a 
definition of this sentiment, we should, perhaps, find 
it a very difficult, if not an impossible task." And 
since he cannot easily give a definition, he offers "a 
description" of it: 2 "I say then, that belief is nothing 
but a more vivid, lively, forcible, fircn, steady concep- 
tion of an object, than what the imagination alone is 
ever able to attain. ' ' Although afterwards he adds : 3 
"I confess, that it is impossible perfectly to explain 
this feeling or manner of conception," he concludes: 4 
"Let us, then, take in the whole compass of this doc- 
trine, and allow, that the sentiment of belief is noth- 
ing but a conception more intense and steady than 
what attends the mere fictions of the imagination, and 
that this manner of conception arises from a cus- 
tomary conjunction of the object with something 
present to the memory or senses." This is the doc- 
trine of the Treatise, and all the terms used in the 
later work were used in the earlier. 5 It is evident, 
therefore, that just as Hume saw, when writing the 
Inquiry, that degree of force and vivacity does not 
express the exact nature of belief ; so he somehow felt, 
when composing the Treatise, that it was not an 
adequate expression for belief in every case. 

Every one recognizes, of course, that there is a 
difference of treatment in the later work. Here the 

1 P. 41. 2 p # 42. 3 Hid. 

* P. 43; cf. p. 48. • Pp. 396 n. 2, — 418. 



186 hume's treatise and inquiry. 

account of belief is more cautiously, more carefully, 
and even more correctly stated than formerly. This 
difference in exposition arose from the author's fuller 
psychological insight. So far, however, as the later 
account is more correct than the earlier, one may infer 
that it involves a change in the doctrine. This much 
is admitted; but the change is only in the way of 
development. It is a variation of detail, not a modi- 
fication of principle. Consequently, it does not in- 
volve any inconsistency between the position of the 
Inquiry and that of the Treatise, on this question. 

Finally, it will be objected that, since, in the later 
work, there is a change in the treatment of belief, 
wherein it is recognized that belief does not always 
consist in degree of " force and vivacity," this new 
position seems to be inconsistent with one of the 
general principles of Hume's system, viz., that there 
is only a difference of degree between impressions 
and ideas. 1 In support of this view is adduced an- 
other form of the argument just examined. In the 
appendix, 2 Hume admits that "more mature reflec- 
tion has discovered" to him an "error" in his reason- 
ing, in the Treatise, where he said that "two ideas 
of the same object can only be different by their 
different degrees of force and vivacity " ; he concedes 
that "there are other differences among ideas, which 
cannot properly be comprehended under these terms ' ' ; 
and he adopts, thereafter, the term feeling to express 
those differences exactly. This admission is worthy 
of consideration; but without examination, too much 
significance ought not to be attached to it. Hume 

1 Cf. Zimels, David Humes Lehre vom Glauben, pp. 78, 79. 

2 I, p. 560. 



BELIEF. 187 

used the foregoing words with reference to belief. 
Subsequently, when he wished to be exact, he em- 
ployed feeling to denote the differentia of belief; on 
all other occasions, however, he employed the same 
terms as in the Treatise. He did not imply, thereby, 
nor mean to express any contradiction in his doctrine 
of belief. In like manner, the correction, in the 
appendix, of the phrase " force and vivacity" is not 
meant to be inconsistent with the general principle, 
in the Treatise, above mentioned. Hume still recog- 
nizes only a difference of degree between an idea and 
its corresponding impression, or between two ideas of 
the same impression. When speaking precisely, that 
difference of degree must be designated by the term 
feeling, which includes force and vivacity, solidity, 
firmness, steadiness, or faster hold, etc., according to 
the constituent elements of the idea. But as a gen- 
eral rule, or speaking roughly, the difference of degree 
may conveniently be indicated by the words force and 
vivacity. This undoubtedly is Hume's position, on 
the question under consideration, when the verbal 
inconsistencies in his writings are removed. 

Exception may possibly be taken to our mode of 
interpretation, in attributing a twofold meaning to 
the expression " force and vivacity.' ' In that case, 
we can only reply that we are explaining the doctrine 
of Hume. We have merely made explicit, what he 
left implicit. For instance, in the appendix, he 
corrected the statement, made in the Treatise, 1 that 
1 'the idea of a particular object' ' can be varied only 
by increasing or diminishing its ' ' force and vivacity, ' ' 
and said that there are other differences among ideas, 

1 P. 3G9. 



188 hume's treatise and inquiry. 

' ' which, cannot properly be comprehended under these 
terms." Yet later, in the Inquiry, he asserted: 1 
"Here therefore we may divide all the perceptions 
of the mind into two classes or species, which are 
distinguished by their different degrees of force and 
vivacity/' That is, in the former case he is speaking 
precisely, in the latter, generally. Moreover, while 
in the appendix he freely acknowledges his error in 
the earlier work, he does not admit that it involves 
any contradiction in his system. On the contrary, he 
implies, in the appendix and in the Inquiry, that his 
doctrine of belief is consistent, both with that in the 
Treatise, and with the fundamental principles of his 
philosophy. 2 The remarks on this subject, in the 
appendix, were made, therefore, not in order to 
modify his former view, but as he said himself, to 
make his reasoning "more convincing," 3 and "to 
guard against all mistakes in the readers." 4 

In the light of what has been said, the similarity 
of Hume's doctrine of belief, in his several writings, 
may be seen at a glance from the following passages : 
In the Treatise he declares: 5 "When ... I com- 
pare an impression with an idea, and find that their 
only difference consists in their different degrees of 
force and vivacity, I conclude upon the whole, that 
belief is a more vivid and intense conception of an 
idea, proceeding from its relation to a present im- 
pression." And further: 6 "It is certain, that the 
belief super-adds nothing to the idea [in reasoning 
concerning matters of fact], but only changes our 

i P. 13; cf. p. 14. 

* Gf. I, pp. 555, 557; IV, pp. 43, 47, 49, 85. 3 I, p. 557. 

* I, p. 555. s P. 403. e p. 402. 



BELIEF. 189 

manner of conceiving it, and renders it more strong 
and lively. . . . There enters nothing into this opera- 
tion of the mind but a present impression, a lively 
idea, and a relation or association in the fancy betwixt 
the impression and idea; so that there can be no sus- 
picion of mistake." In the appendix he says: 1 "I 
conclude, by an induction which seems to me very 
evident that an opinion or belief is nothing but an 
idea, that is different from a fiction, not in the nature, 
or the order of its parts, but in the manner of its 
being conceived. But when I would explain this 
manner, I scarce find any word that fully answers 
the case, . . . An idea assented to feels different 
from a fictitious idea, . . . and this different feeling 
I endeavor to explain by calling it a superior force, 
or vivacity, or solidity, or firmness, or steadiness." 
And in the Inquiry he states: 2 "The difference be- 
tween fiction and belief lies in some sentiment or feel- 
ing, which is annexed to the latter, not to the former, 
and which depends not on the will, nor can be com- 
manded at pleasure. . . . "Were we to attempt a 
definition of this sentiment, we should, perhaps, find it 
a very difficult, if not an impossible task. ' ' Finally, 3 
"Let us . . . take in the whole compass of this doc- 
trine and allow, that the sentiment of belief is noth- 
ing but a conception more intense and steady than 
what attends the mere fictions of the imagination, 
and that this manner of conception arises from a 
customary conjunction of the object with something 
present to the memory or senses." 
The opinion of some critics 4 that Hume's doctrine 

1 T, p. 397. 2 p. 4i. 3 p. 43. 

*Cf. Brodo, Dry Unlcrschicd d. Lehren U ., p. 50. 



190 hume's treatise and inquiry. 

of belief, as expressed in the Inquiry, is the natural 
transition to the view of the philosophers of the Scot- 
tish School is manifestly a product of the imagina- 
tion, rather than of the understanding. There always 
remained a fundamental difference between the view 
of Hume, and that of Reid. According to the former, 
the feeling or sentiment of belief, although instinctive, 
is derivative, arising through association and custom ; 
according to the latter, belief is always immediate 
and ultimate. "With Hume, belief is a product of the 
sensitive, rather than of the cogitative part of our 
nature; with Reid, it has its origin in a priori intel- 
lectual principles. 

§ 33. The Cause of Belief.— Since belief, as stated 
in the Treatise, 1 consists in the force and vivacity of 
a perception, impressions of sense and ideas of mem- 
mory are believed because they have this force and 
vivacity in themselves. The cause of belief of reason- 
ing concerning matters of fact, or ideas of imagina- 
tion is the force and vivacity of an impression of 
sense or memory, and the customary transition from 
this impression to a related idea. Thus Hume as- 
serts: 2 "I would willingly establish it as a general 
maxim in the science of human nature, that when 
any impression becomes present to us, it not only 
transports the mind to such ideas as are related to 
it, but likewise communicates to them a share of its 
force and vivacity." Then by means of a set of 
experiments, he professes to show that a present im- 
pression and the causal relation are requisite to pro- 
duce belief. 3 The relations of resemblance and con- 
tiguity, although inadequate by themselves, strengthen 

i Pp. 387, 417, 448. 2 p. 399. 3 p p . 402, 403. 



BELIEF. 191 

the relation of cause and effect. Hence, "the picture 
of an absent friend" enlivens the idea of him, because 
of resemblance. 1 "The ceremonies of the Roman 
Catholic religion" inspire the devotion and quicken 
the fervor of "the devotees of that strange supersti- 
tion." 2 When one is "a few miles from home," 
whatever relates to it touches one more nearly, be- 
cause of contiguity, than when one is "two hundred 
leagues distant." 3 "A man, whose memory presents 
him with a lively image of the Red Sea, and the 
Desert, and Jerusalem, and Galilee, can never doubt 
of any miraculous events, which are related either by 
Moses or the Evangelists."* In like manner, want of 
mblance and contiguity has an opposite effect upon 
belief. This is why men show a "universal careless- 
9 and stupidity" with regard to a future state, yet 
"are everywhere concerned about what may happen 
after their death/' provided it has reference to the 
present world. 5 

In the Inquiry 6 Hume states that "sensible objects 
have always a greater influence on the fancy than 
any other, ' ' and seems to hold the same view as f orm- 
erly regarding the cause of belief of impressions. 7 
The cause of belief in reasoning concerning matters 
of fact he explains in the following manner: 8 "Does 
it happen, . . . that, when one of the objects is 
pjvsented to the senses or memory, the mind is not 
only carried to the conception of the correlative, but 
reaches a steadier and stronger conception of it than 
what otherwise it would have been able to attain? 



1 P. 100. 


•Ibid. 


3 P. 401. 


« P. 41<). 


■ Pp. 412, 413. 


> P. 44. 


' Of. pp. 45, 124, 


s P. 43. 





192 hume's treatise and inquiry. 

This seems to be the ease with that belief, which arises 
fr.om the relation of cause and effect. And if the 
case be the same with the other relations or principles 
of association, this may be established as a general 
law, which takes place in all the operations of the 
mind." A number of illustrations, all but one of 
which are taken from the Treatise, are thus given in 
verification of the general law. 1 The position of both 
works, on the question of the cause of belief, is the 
same. 

§ 34. Conclusion.— The results of the discussion 
may be summarized as follows:— 

1. Belief of Impressions. In the Treatise, the 
highest degree of belief is attributed to impressions 
of sense and ideas of memory. In the Inquiry, the 
same view is implied, although not explicitly stated. 

2. Belief of Ideas. The special subject for exam- 
ination, in both works, is belief of the inferred idea 
in reasoning concerning matters of fact. Hume de- 
scribes the manner of conception which constitutes 
belief, in the Treatise, as a superior degree of force, 
vivacity, 2 strength, vividness, 3 liveliness, 4 firmness, 
solidity, 5 intensity, 6 intenseness, 7 steadiness, 8 or as 
feeling; 9 in the appendix, as a feeling, 10 that is, a 
superior force, vivacity, solidity, firmness, steadi- 
ness, 11 strength, or faster hold ; 12 and in the Inquiry, 
as a feeling, 13 that is, a more vivid, lively, forcible, 
firm, steady, 14 or intense conception, 15 "than what 
attends the mere fictions of the imagination. ' ' 

i Pp. 43-45. 2 p. 397. a p. 398. 

* P. 399. s p. 406. 6 p. 418. 

* P. 449. s P. 396 n. 2. » P. 403. 
10 1, p. 555. " P. 398. 12 P. 557. 
13 P. 42. " Ibid. 15 P. 43. 



BELIEF. 193 

3. The Cause of Belief. The cause of belief, the 
author regards, in both the Treatise 1 and Inquiry, 2 as 
the same. Impressions of sense and ideas of mem- 
ory produce belief through their own inherent force 
and vivacity. Ideas of imagination are believed when 
they are related to impressions of sense or ideas of 
memory by means of the causal relation. In a wider 
sense, belief is spoken of in the earlier, work as a 
product of nature, and in the later, as a natural in- 
stinct;— custom being the cause, or the equivalent of 
the "product of nature/' and also of the "natural 
instinct." 

While the positions of the Treatise, appendix, and 
Inquiry, on the subject of belief, are substantially the 
same, the differences of treatment are not without 
significance. When Hume, in the appendix, corrected 
the statement in the earlier work, that "the idea of 
a particular object' ' can be varied only by increasing 
or diminishing its "force and vivacity," he made a 
step forward in psychological analysis. This is the 
only significance of the correction. When, in the ap- 
pendix and Inquiry, he substituted feeling for force 
and vivacity to express the differentia of belief, he 
recognized more fully than formerly the emotional 
element in belief. This is the chief significance of 
the change. And when, in the later writings, he 
employed purposely a number of terms to express this 
f<<ling, he acknowledged explicitly what he indicated 
only implicitly, in the earlier work, viz., that there 
are several forms, or kinds of belief. This is the chief 
significance of that "variety of terms," which he 
thought would seem "unphilosophical," but which 

i Pp. 471, 474. 2 Tp. 40, 40, 124, 

13 



194: hume's treatise and inquiry. 

he made use of in order that his readers might ' ' agree 
about the thing. ' n In his discussion of belief, Hume 
made two things clear: (1) He was fully conscious 
that he was on the right track; he felt that if the 
matter were not quite thus, it was somehow thus; 
(2) he was dissatisfied with his own solution. This 
problem is one of the very few subjects in the philos- 
ophy of human nature that underwent any develop- 
ment after it had been stated in the earlier work. 
But lacking experimental introspection, Hume was 
obliged to leave the problem of belief for his successors 
to unravel, 
i IV, p. 42. 



CHAPTER IX. 

PROBABILITY, NECESSITY, AND THE REASON OF ANIMALS. 

§ 35. Probability.— In the Treatise Hume intro- 
duces, between the discussions on belief and necessary 
connection, three sections on probability, "in order 
to bestow" on his system "its full force and evi- 
dence." 1 In an earlier part of the work, in accord- 
ance with the usual method of philosophers, he di- 
vided "human reason"— the objects of knowledge or 
reasoning — into knowledge, and probability. 2 Now, 
in order to mark "the several degrees of evidence," 
as commonly understood, he thinks it more convenient 
"to distinguish human reason into three kinds, viz., 
that from knowledge, from proofs, and from proba- 
bilities." By knowledge, he means that "assurance 
arising from the comparison of ideas;" by proofs, 
"those arguments, which are derived from the rela- 
tion of cause and effect, and which are entirely free 
from doubt and uncertainty"; and by probability, 
"thai evidence, which is still attended with uncer- 
tainty." 3 Accordingly, the present subject of discus- 
sion is probability in this last or narrower sense. 
Probability, as thus defined, Hume divides into philo- 
sophical probability, and unphilosophical probability; 
and philosophical probability into that of chances, 
and that of causes. Consequently, the topics for 
consideration are philosophical probability of chance, 

1 Pp. 423, 449, 450. \ 2 Of. pp. 372, 423. 3 P. 423. 

196 



196 hume's treatise of human nature. 

philosophical probability of cause, and unphilosoph- 
ical probability. They may be treated in their order. 

1. The Account of Probability in the Treatise. 
1. Probability of Chance. In reasonings concerning 
philosophical probability of chances, according to 
Hume, there are two points for explanation: (1) The 
nature of chance; (2) the effect upon the mind of a 
superior number of chances as influencing belief. 
Chance has three characteristics: 1 (1) It is merely 
"the negation of a cause, and produces a total indif- 
ference in the mind''; (2) "one negation of a cause 
and one total indifference can never be superior or 
inferior to another," that is, all chances are equal; 
(3) among chances that are to be the foundation of 
reasoning, "there must always be a mixture of 
causes. ' ' On observing a superior, number of chances, 
belief arises "neither by demonstration nor proba- 
bility," 2 but from imagination. 3 And the act of 
imagination, in conclusions concerning the probability 
of chances, includes three elements: 4 (1) A summing 
up, or fusion, of the favorable instances; (2) a sum- 
ming up of the unfavorable instances; (3) the sub- 
traction of the latter sum, or sums from the former. 
The remainder represents the probability, and the 
degree of assurance or strength of belief. 

2. Probability of Cause. Since it is "commonly 
allowed by philosophers, that what the vulgar call 
chance is nothing but a secret and concealed cause," 
Hume remarks: 5 "What I have said concerning the 
probability of chances can serve to no other purpose, 
than to assist us in explaining the probability of 

i P. 425. 2 Ibid. 3 pp. 427, 428. 

* P. 428; cf. 436. 5 p. 428. 



PROBABILITY, NECESSITY, ANIMAL REASON. 197 

causes." He notes that there are several kinds of 
probability of causes, and treats of the following 
three: 1 (1) Imperfect habit, that in which the num- 
ber of instances necessary to produce a fixed or per- 
fect habit have not been experienced; (2) contrary 
causes, that in which the observed instances are con- 
trary to one another; (3) analogy, 2 that in which the 
resemblance between the observed instances is inexact 
or incomplete. All reasoning concerning probability 
of causes is derived from the same origin, viz., "the 
association of ideas to a present impression."* In 
other words, all reasoning concerning the probability 
of causes, like that concerning the probability of 
chances, is based upon imagination and custom. 

3. Unphilosophical Probability. Probabilities of 
chance and of cause "are received by philosophers, 
and allowed to be reasonable foundations of belief 
and opinion. " There are other sorts, however, that 
have not had "the good fortune to obtain the same 
sanction." These are classified under the term un- 
philosophical probability. 4 In unphilosophical prob- 
ability the evidence, and consequently the degree of 
belief, "diminishes by the diminution of the force 
and intenseness of the idea," as in the following in- 
stances: 5 "[When] the present impression is faint 
and obscure; or the experience in some measure ob- 
literated from the memory; or the inference derived 
from general rules, and yet not conformable to them." 
All these sorts of unphilosophical probability "are 
derived from the same principles" as philosophical 

I P. 429. 2 p. 439. 3 p. 428. 

« P. 439. « P. 449. 



198 hume's treatise and inquiry. 

probability, 1 and consequently do not call for further 
explanation. 

II. The Account of Probability in the Inquiry. 
Hume, in the Inquiry, does not make any distinction 
between philosophical, and unphilosophical proba- 
bility, and omits entirely a treatment of the latter. 
This does not seem to be of any special significance, 
however, since he said, in the Treatise, that unphilo- 
sophical probability is "derived feom the same prin- 
ciples" as philosophical probability. In a foot-note 2 
he refers to Locke 's division of arguments into demon- 
strative and probable, and states that, in accordance 
with the language in common use, "we ought to divide 
arguments into demonstrations, proofs, and probabili- 
ties." Then he gives a brief account of probability 
of chance, and probability of cause. He asserts, as 
in the Treatise, that "though ther.e be no such thing 
as chance in the world ; our ignorance of the real cause 
of any event has the same influence on the under- 
standing, and begets a like species of belief or opin- 
ion"; that is, all chances are equal, and as such have 
an equal influence on the mind. 3 Probability of 
chance he explains as follows: 4 "There is certainly 
a probability, which arises from a superiority of 
chances on one side ; and according as this superiority 
increases, and surpasses the opposite chances, the 
probability receives a proportionable increase, and 
begets still a higher degree of belief or assent to that 
side, in which we discover the superiority." And he 
concludes, with a more than usual degree of diffidence, 
that the philosophy of human nature "may, per,haps, 

i P. 439. 2 P. 47. 

s P. 48. * P. 47. 



PROBABILITY, NECESSITY, ANIMAL REASON. 199 

in some measure," be able to account for "this opera- 
tion ' ' of the mind. 1 Hume then declares that reason- 
ing concerning the probability of causes is the same 
as that concerning the probability of chance; 2 and 
that all the received systems of philosophy are de- 
fective, since none of them can explain the nature of 
this mental operation. 3 

III. Conclusion. It is evident that Hume's doc- 
trine of probability is the same in both works. The 
briefer, statement, in the Inquiry, may be attributed 
to several causes: (1) The different circumstances 
under which the books were written; (2) unphilo- 
sophical probability is derived from "the same prin- 
ciples' ' as philosophical probability, and consequently 
did not call for specific treatment a second time; (3) 
the account of probability given in section vi is sup- 
plemented by several incidental references in sections 
viii, 4 ix, 5 and x. 6 

Br.ede thinks that there is an important difference 
between the doctrine of probability as presented in 
the later work, and that in the earlier. He states 7 
that, according to the exposition in the Inquiry, the 
experiences relating to the different sides do not fuse 
in a single picture, as they may be said to do in the 
Treatise, but form pictures in the mind of both pos- 
sibilities, and that picture with the more belief at- 
tached to it gives the decision directly, or immediately 
turns the scale. It may be admitted that there is some 
ground for this view, if one examines only the account 

1 P. 48. 2 Ibid. 

1 P. 40. 4 p. 7i ; C f. j f p . 430. 

5 P. 85; of. I., p. 4.30. 

* Pp. DO, 01, 04, 105; of. I, p. 428. 

7 Dcr Unterschicd d. Lilian II., p. 40. 



200 hume's treatise and inquiry. 

given in section vi. But when notice is taken also 
of the references in section x, it is perceived that 
the position of both works is identical. In the 
Treatise, 1 a conclusion from philosophical probability 
is the result of three processes: (1) A fusion, or union 
of the instances favorable to one side; (2) a fusion of 
the contrary instances; (3) the fusion of these two 
sums, or more correctly, the subtraction of the smaller 
sum from the greater. The remainder represents the 
degree of probability of the conclusion or judgment. 
In the Inquiry, 2 the concurrence of several views in 
one particular event " begets immediately, by an inex- 
tricable contrivance of nature, the sentiment of belief, 
and gives that event the advantage over its antagonist, 
which is supported by a smaller number of views, and 
recurs less frequently to the mind. ' ' That is to say, 
in the treatment of probability, both of chance and 
of cause, given in the Inquiry, the third process is not 
explicitly designated. It may be noted, however, that 
neither, is the third process mentioned in the first ex- 
ample of probability of causes which is given in the 
Treatise. 3 The three processes are described fully in 
the account of probability of chances; the first two 
are described in the first example of probability of 
causes ; and then Hume remarks : 4 ' ' This operation of 
the mind has been so fully explained in treating of 
the probability of chance, that I need not here en- 
deavor, to render it more intelligible. ' ' Hence, the 
third process is implied, although not distinctly stated. 
It is stated afterwards. 5 In the Inquiry also, in the 
discussion on probability, it is implied, and in the dis- 

i P. 428. 2 P. 48. 3 P. 432. 

* P. 432. 5 P. 436. 



PROBABILITY, NECESSITY, ANIMAL REASON. 201 

cussion on miracles it is expressly mentioned. The 
author asserts: 1 "All probability, then, supposes an 
opposition of experiments and observations, where the 
one side is found to overbalance the other, and to pro- 
duce a degree of evidence, proportioned to the su- 
periority. ... In all cases, we must balance the 
opposite experiments, where they are opposite, and 
deduct the smaller number from the greater, in order 
to know the exact force of the superior evidence.' ' 

Brede 2 also alleges that the defective treatment of 
probability, in the Inquiry, is a result of Hume's 
altered view of the concept of belief. We have al- 
ready shown that the doctrine of belief in the Inquiry 
and appendix is essentially the same as that in the 
Treatise. 3 It is only the mode of expressing the doc- 
trine which is changed. And it is only necessary now 
to remark that, in the discussion on probability in the 
Inquiry, Hume again regards belief as "nothing but 
a firmer and stronger conception of an object than 
what attends the mere fictions of the imagination." 4 
Having dealt so fully, in the Treatise, with the sub- 
ject of probability, the author did not think it neces- 
sary to repeat, in the briefer work, all he had said in 
the earlier. 

36. Liberty and Necessity,— After the discussion 
of the relation of cause and effect, the order of treat- 
ment differs considerably in the two works. The sec- 
tion in the Treatise on "Kules by which to judge of 
Causes and Effects" is omitted in the Inquiry, and in 
its stead is inserted a section on "Liberty and Neces- 

1 P. 90; cf. pp. 03, 94, 105. 

2 Dcr Unterschied d. Lehren //., p. 40. 

3 Pp. 176-182, above. * P. 48; cf. p. 43. 



202 hume's treatise and inquiry. 

sity," which was transferred from Book II of the 
Treatise of Human Nature. Selby-Bigge 1 asserts that 
"the question of the employment of general rules," a 
subject of "great speculative as well as practical in- 
terest/' is ignored in the Inquiry. He thinks that 
the omission of the section dealing with this topic is 
a part of Hume's policy (1) to evade a difficult gen- 
eral question which he has already shown his anxiety 
to avoid in his omission of section iii, and (2) to 
escape the perplexities arising from his theory of 
causation regarded as a natural, as well as a philo- 
sophical relation. The reader has already noted that 
the subject of "general rules" was not entirely ig- 
nored in the appendix, 2 and that Hume, in the In- 
quiry, still recognized the distinction between cause 
as a philosophical, and cause as a natural relation. 3 
Moreover, in the substituted section, the twofold defi- 
nition of necessity which makes "an essential part" 
of cause, again marks the distinction between these 
two forms of relation. 4 Furthermore, it may be ob- 
served that in the second edition of the Inquiry — 
1751— -a foot-note was added to the section on "The 
Eeason of Animals," in order to explain "the great 
difference in human understandings," when reason- 
ing concerning l ' facts or causes. ' ' This note contains 
a series of propositions somewhat analogous to the list 
of general rules given in the Treatise. That these 
Propositions do not perfectly correspond with the 
"general rules," and that Hume does not again enu- 
merate the latter is by no means singular, since at 
the close of his account of this subject in the earlier 
work he remarked: 5 "Here is all the Logic I think 

1 Hume's Enquiries, Introd. 2 P. 176. 

3 Cf. pp. 158-159, above. * P. 79. * P. 468. 



PROBABILITY, NECESSITY, ANIMAL REASON. 203 

proper to employ in my reasoning ; and perhaps even 
this was not very necessary, but might have been sup- 
plied by the natural principles of our understand- 
ing.' ' The section on "General Rules" is little more 
than a sequel to that on " Unphilosophical Probabil- 
ity." 1 Consequently, when the section on unphilo- 
sophical probability was omitted in the briefer work, 
the omission of that on general r.ules followed natu- 
rally. An additional reason why Hume does not 
again enumerate the general rules is suggested by 
himself, when he says in the Treatise : 2 ' l All the rules 
of this nature are very easy in their invention, but 
extremely difficult in their application." In the In- 
quiry, it was not at all the author's aim to deal with 
questions of this character. 

In the Treatise of the Passions Hume begins his 
exposition of the will with a discussion on liberty and 
necessity. He defines will, states that "the operations 
of external bodies are necessary, ' ' and then attempts 
to prove that the actions of mind are "on the same 
footing" as those of matter. 3 He finds "two par- 
ticulars," or elements, essential to necessity, viz., "the 
constant union, and the inference of the mind"; and 
holds that, "wherever we discover these two factors 
we must acknowledge a necessity." 4 Hence, he con- 
tends that "the actions of matter have no necessity" 
except constant union, and that it is "the observa- 
tion" of this constant union "which produces the 
inference." He next professes to show that "our 
actions have a constant union with our motives, tem- 
pers, and circumstances/'"' and that "as the union 

i Of. p. 4ir>. 2 p. 4G8. 3 p. 181. 

4 P. 182. s ma. 



204 hume's treatise and inquiry. 

betwixt motives and actions has the same constancy, 
as that in any natural operations, so its influence on 
the understanding is also the same, in determining 
us to infer the existence of one from that of an- 
other. ,?1 Consequently, he affirms: 2 "I dare be posi- 
tive, no one will ever endeavor to refute these reason- 
ings otherwise than by altering my definitions, and 
assigning a different meaning to the terms of cause, 
and effect, and necessity, and liberty, and chance." 
Hume then states three reasons for the prevalence of 
the doctrine of liberty: 3 (1) The difficulty of thinking, 
after an act has been performed, that one was neces- 
sitated to perform it; (2) a false sensation of the 
liberty of indifference; (3) the mistaken belief that 
libertarianism is more favorable than necessitarianism 
to the interests of morality and religion. Finally, he 
insists that his doctrine of necessity "is so essential 
to religion and morality, that without it there must 
ensue an absolute subversion of both, and that every 
other supposition is entirely destructive to all laws 
both divine and human." 4 

The treatment of liberty and necessity is somewhat 
fuller in the Inquiry than in Book II of the Treatise 
of Human Nature. This fact is due chiefly to the 
insertion of some of the material that was omitted in 
the abbreviated discussion on the probability of 
causes, 5 and to the development of the religious as- 
pect of the question of free will. In spite of these 
differences, the argument is essentially the same as 
that in the earlier work. The author finds, as before, 
that the two elements of necessity ar.e "the constant 

i P. 185; cf. IV, p. 166. 2 p. igg. s p p . 188, 189. 

* P. 191. s cf. I, p. 430; IV, p. 71. 



PROBABILITY, NECESSITY, ANIMAL REASON. 205 

conjunction of similar objects, and the consequent 
inference from one to the other/' 1 This is the only- 
kind of necessity that is discoverable in nature, and 
it exists in human conduct equally as in the external 
world. 2 Then Hume assigns reasons "why all man- 
kind, though they have ever, without hesitation, ac- 
knowledged the doctrine of necessity, in their whole 
practice and reasoning, have yet discovered such a 
reluctance to acknowledge it in words, and have 
rather shown a propensity, in all ages, to profess the 
contrary opinion. ' ' 3 And he concludes with an argu- 
ment to show, "that the doctrines, both of necessity 
and of liberty, as above explained, are not only con- 
sistent with morality and religion, but are absolutely 
essential to its support." 4 

As usual, in the Inquiry there are differences in the 
form of statement. The more significant of these are 
the following: 5 (1) The omission of the preliminary 
definition of will. 6 A definition of will was given in 
the earlier, work, because the subject of liberty and 
necessity, occurring as it does in connection with the 
will, was discussed under that head. (2) The inser- 
tion of a more specific definition of liberty than that 
given formerly. 7 Hume now thought that "a few 
intelligible definitions" would soon "put an end to the 
whole controversy."* (3) The more emphatic, and 
the repeated assertion that all mankind "have always 
been of the same opinion ' ' with regard to the doctrine 
of liberty and necessity, and that "the whole con- 
troversy has hitherto turned merely upon word* 

1 P. 67. 2 Pp. 07-75. 3 P. 75. 4 P. 79. 

■Of. Selby-Bigge, Hume's Enquiries, p. rviii. 

6 II, p. lsi. t i>. /S; of. II. p. 188. 8 P. GO. 

9 Pp. GO, 07, 68, r2, 73, 75, 77, 7S; cf. II, pp. 181, 188, 100. 



206 hume's treatise and inquiry. 

(4) A much fuller discussion of the religious aspect 
of the question. 1 

The last change specified is by far the most impor- 
tant in this section of the Inquiry. Two causes are 
assigned— the second in a foot-note 2 — why "all man- 
kind, though they have ever, . . . acknowledged 
the doctrine of necessity, in their whole practice and 
reasoning, have yet discovered such a reluctance to 
acknowledge it in words. ' ' 3 These are similar to the 
first two causes assigned in the earlier work. The 
third cause mentioned in Book II of the Treatise of 
Human Nature, why the doctrine of necessity has not 
been more generally accepted, viz., its supposed dan- 
gerous consequences for morality and religion, Hume 
now makes a subject of special treatment. He affirms 
that the doctrines of both liberty and necessity "as 
above explained, ' ' are not only consistent with moral- 
ity, but "are absolutely essential to its support." 
Liberty means "a power of acting or not acting, ac- 
cording to the determinations of the will"; 4 while 
necessity is "the constant conjunction of similar ob- 
jects, and the consequent inference from one to the 
other." 5 Yet, with liberty and necessity so defined, 
and while insisting that this doctrine is essential to 
the support of morality and religion, the author pre- 
tends not "to have obviated or removed all objec- 
tions" to his theory. 6 He contends, however, that his 
doctrine is not worse off, in this respect, than is any 
other, and asserts that there are "inextricable diffi- 
culties, and even contradictions" in every system. 
"To reconcile the indifference and contingency of 

i Pp. 79-84; cf. II, pp. 189-192. 2 p. 77. 

s P. 75. * P. 78. s p. 67. 6 P. 81. 



PROBABILITY, NECESSITY, ANIMAL REASON. 207 

human actions with prescience," he declares, "or to 
defend absolute decrees, and yet free the Deity from 
being the author of sin, has been found hitherto to 
exceed all the power of philosophy." 1 Notwith- 
standing some minor differences the doctrine of lib- 
erty and necessity is the same in both works. 

There is no valid ground for the statement of 
Hyslop 2 that, on this question, Hume is inconsistent 
with his doctrine of necessity as explained in the 
Treatise. Necessity, as defined in the Inquiry, con- 
sists only in the constant conjunction of like objects 
or phenomena, and in the inference of the mind from 
one to the other. 3 This is exactly its meaning in the 
Treatise. 4 But this is not the doctrine of determinism 
as commonly understood. It is equivalent to uniform 
or rational conduct, and is perfectly consistent with 
some forms of libertarianism. In fact, it is not lib- 
ertarianism which Hume refutes, but chance, or lib- 
erty of indifference. His doctrine of necessity is the 
same as that of liberty of spontaneity. In Book II 
of the Treatise of Hitman Nature he asserts: 5 "Few 
are capable of distinguishing betwixt the liberty of 
spontaneity, as it is called in the schools, and the lib- 
erty of indifference; betwixt that which is opposed to 
violence, and that which means a negation of neces- 
sity and cause. The first is even the most common 
sense of the word; and as it is only that species of 
liberty, which it concerns us to preserve, our thoughts 
have been principally turned towards it, and have 

i P. 84. 

2 Hume's Treatise of Morals, p. 33; cf. Grimm, Zur CcscJi. 
d. Erkenntnisproblems, p. 587. 
■ P. 70. i Of. I, pp. 450-464; II, p. 182. « P. 188. 



208 hume's treatise and inquiry. 

almost universally confounded it with the other." 
Similarly, in the Inquiry, he says: 1 "By liberty, then, 
we can only mean a power of acting or not acting, 
according to the determinations of the will; that is, 
if we choose to remain at rest, we may ; if we choose 
to move, we also may. Now this hypothetical liberty 
is universally allowed to belong to every one, who is 
not a prisoner and in chains. Here then is no subject 
of dispute. . . . And if the definition above men- 
tioned be admitted; liberty, when opposed to neces- 
sity, not to constraint, is the same thing with chance ; 
which is universally allowed to have no existence." 

In short, Hume's doctrine of liberty and necessity 
was clearly in advance of the thought of his age. Far 
from lowering the dignity of mind, on the contrary, 
Hume elevated the qualities of matter. In accord- 
ance with the tendencies of modern science, and in 
conformity with the spirit of an idealistic philosophy, 
the author of the Treatise of Unman Nature rever- 
ently declared: 2 "I do not ascribe to the will that 
unintelligible necessity, which is supposed to lie in 
matter. But I ascribe to matter., that intelligible 
quality, call it necessity or not, which the most rigor- 
ous orthodoxy does or must allow to belong to the 
will. I change, therefore, nothing in the received 
systems, with regard to the will, but only with regard 
to material objects." And in the later work, with 
equal clearness and candor, he asserted: 3 "But surely 
we ascribe nothing to the actions of the mind, but 
what every one does, and must readily allow of. We 
change no circumstance in the received orthodox sys- 
tem with regard to the will, but only in that with re- 
gard to material objects and causes." 

i Pp. 78, 79. 2 n, p. 190. 3 P. 80. 



PROBABILITY, NECESSITY, ANIMAL REASON. 209 

The examination of the doctrine of liberty and 
necessity, in the Inquiry, follows very appropriately 
that of the idea of cause and effect, as one of the prac- 
tical applications of Hume's theory of causation. 
And it might very well have been inserted in the later 
work for that purpose. The author claims, at the 
outset, that his argument has "novelty," that it 
"promises at least some decision of the controversy, 
and will not much disturb [the reader's] ease by any 
intricate or obscure reasoning." 1 But although he 
entered upon this discussion with peace on his lips, it 
is much to be feared he had war in his heart. For 
the only important change of treatment which the 
subject received is the fuller development of the eth- 
ical and religious aspect of the question. The argu- 
ment, in its new form, constitutes a piece with the 
sections on "Miracles" and "The Practical Conse- 
quences of Natural Religion. ' ' The essay on miracles 
Hume intended to publish in the Treatise, but was 
"afraid" it would give "too much offence" as the 
world was then disposed. 2 The Treatise, however, 
did not reach "such distinction, as even to excite a 
murmur, among the zealots. ' ' 3 Hume was determined 
that the Inquiry should succeed better. And it did. 
The author, it is true, on his return from Italy, "had 
the mortification to find all England in a ferment, on 
account of Dr. Middleton's Free Enquiry," while his 
own performance "was entirely overlooked and neg- 
lected." 4 Very soon, however, he learned that the 
sale of his works was increasing, and that new edi- 
tions of them were demanded. Millar printed off a 

1 P. GO. 2 Burton, Life, I, p. G3. 

3 My Own Life. * Ibid. 

14 



210 hume's treatise and inquiry. 

second edition of the Inquiry, in 1750, but delayed 
publishing until the following year "because of the 
earthquakes." 1 "Answers by Reverends, and Right 
Reverends ' ' soon came out two or three in a year, and 
Hume inferred from "Dr. Warburton's railing," that 
his books— "all but the unfortunate Treatise ' '-—were 
beginning to be esteemed "in good company." 2 

§ 37. The Reason of Animals.— In order to confirm 
the truth of his system by enlarging the sphere of his 
experiments, 3 Hume devoted the last section of Part 
III in the Treatise to a discussion of the reason of 
animals. "This doctrine," he says, 4 "furnishes us 
with a kind of touchstone, by which we may try every 
system in this species of philosophy." His line of 
argument is as follows: Men are conscious that, in 
adapting means to ends, they are guided by reason. 
Animals perform like actions ; therefore, they are pos- 
sessed of reason like that of men. Thus he asserts : 5 
"It is from the resemblance of external actions of 
animals to those we ourselves perform, that we judge 
their internal likewise to resemble ours ; and the same 
principle of reasoning, carried one step farther, will 
make us conclude that since our internal actions re- 
semble each other, the causes, from which they are 
derived, must also be resembling. ' ' 

It may be observed that, in an earlier part of the 
work, Hume recognized two kinds of reasoning, dem- 
onstrative, and probable ; 6 and that it is only the latter, 
probable or experiential reasoning, which he treats in 
the present section. He now distinguishes between 
those actions of animals "which are of a vulgar 

i Burton, Life, I, p. 300. 2 My Own Life. 3 P. 468. 

4 P. 469. s Ilid. e I, pp. 373, 376. 



PROBABILITY, NECESSITY, ANIMAL REASON. 211 

nature/' and " those more extraordinary instances of 
sagacity," known as instinctive acts. The former 
actions proceed from reasoning similar to ''that which 
appears in human nature/' that is, fr.om a present 
impression of sense or memory and the observation of 
the constant conjunction of similar objects in past 
experience. 1 The latter actions Hume does not at- 
tempt to explain, though he seems to regard them as 
closely related to the former. For "reason," he de- 
clares, "is nothing but a wonderful and unintelligible 
instinct in our souls. ' ' True, it is an instinct which 
arises from "past observation and experience," as 
contrasted with instinct proper which arises imme- 
diately from nature. But no one can explain why 
nature should produce one kind of instinct in this 
way through habit, and produce another kind of in- 
stinct immediately and directly. 2 

The philosophy of human nature, therefore, ex- 
plains the reasoning of men and of animals on the 
same principle. Moreover, according to the author, 
the reasoning of men and animals cannot be satisfac- 
torily explained otherwise than on a single principle. 
For if on the one hand, the reasoning process, or the 
reasoning faculty in man is of such a profound or 
abstract nature that animals cannot be regarded as 
possessing it, then neither can children nor some un- 
educated persons be thought to have it. And if on 
the other hand, reason is attributed to these latter, it 
cannot logically be denied to many species of animals. 
The only kind of reasoning, however, that animals are 
capable of performing is inference, or transition from 
a present impression of sense or memory to a related 

1 P. 470. 2 p. 47i. 



212 hume's treatise and inquiry. 

idea by means of association and custom. 1 And this is 
precisely that in which Hume professes to have al- 
ready shown the reasoning of men concerning matters 
of fact to consist, Here then he claims to have not 
merely "a strong confirmation, ' ' but rather "an in- 
vincible proof" of the truth of his system. 2 

In the Inquiry also, the author hopes that the ex- 
amination of the reason of animals "will serve to con- 
firm' ' his "former observations. ' ' Any theory which 
explains "the operations of the understanding, or the 
origin and connection of the passions in man," will 
acquire additional authority if it "is requisite to 
explain the same phenomena in all other animals." 3 
He regards animals as performing two kinds of acts : 
those learned by experience, and those prompted by 
instinct. 4 The former proceed from education and 
custom; thus Hume remarks: 5 "It is custom alone, 
which engages animals, from every object, that strikes 
their senses, to infer its usual attendant, and carries 
their imagination, from the appearance of the one, 
to conceive the other, in that particular, manner, 
which we denominate belief." And he adds: "No 
other explication can be given of this operation, in all 
the higher, as well as lower classes of sensitive beings, 
which fall under our notice and observation." On 
the other hand, instincts are derived from "the orig- 
inal hand of nature." Of them no explanation is 
offered. Hume still speaks of experimental reasoning 
as "a species of instinct." It is different of course 
from instinct proper, in that it arises from experience 
and custom; while instinct proper, coming from the 
original hand of nature, is capable of little or no im- 
provement. 

iP. 471. 2 Ibid. * P. 85. * Pp. 85, 88. s P. 87. 



PROBABILITY, NECESSITY, ANIMAL REASON. 213 

Besides a slight change in the order of discussion, 
the only difference of note, in the Inquiry, is the 
explicit recognition that there are two kinds of reason- 
ing, viz., reasoning concerning ideas— "comparisons 
of ideas/'— and reasoning concerning matters of fact 
—"experimental reasoning." 1 Relations or compari- 
sons of ideas Hume regards as "the proper objects of 
[man's] intellectual faculties." 2 And he asserts that 
animals do not reason in this sense of the term. 
Although the distinction here drawn, between demon- 
strative and probable reasoning, is not made in the 
section on the reason of animals in the Treatise, it 
was made repeatedly in other parts of the work. 3 
Even in the section of the Treatise under discussion, 
Hume implies that animals do not reason in the nar- 
rower meaning of the word, when he states that "they 
can never by any arguments form a general conclu- 
sion, that those objects, of which they have had no 
experience, resemble those of which they have." 4 
Notwithstanding some modifications, therefore, in the 
manner of treatment, the standpoint of the later 
work, on this question, does not differ in any essential 
respect from that of the earlier. 

Huxley contends that, while Hume seemed to re- 
gard the reasoning of men and of animals as being 
different in kind, he really held that it is only different 
in degree. "It will be observed," he says, 5 "that 
Hume appears to contrast the ' inference of the ani- 
mal' with the 'process of argument or reasoning in 
man.' But it would be a complete misapprehension 

1 Pp. 86, 88. * P. 88. 

■ Of. pp. 372, 373, 375, 370, 300, 472, 473. * P. 471. 

6 Hume, p. 107; of. Grimm, Zur Gcsch. d. Erkcnntnisprob- 
U uts, p. 567. 



214 hume's treatise and inquiry. 

of his intention, if we were to suppose, that he thereby 
means to imply that there is any real difference be- 
tween the two processes. ' ' If one examines only the 
exposition of the Treatise, one may find some ground 
for, Huxley's assertion. In the earlier work, the 
author states that no truth appears to him to be more 
evident "than that beasts are endowed with thought 
and reasoning, as well as men. ' n When one turns to 
the Inquiry, however, one discovers that Hume con- 
trasts the "inference of the animal" with the "process 
of argument" in man, and denies that animals reason 
in the latter sense. As has just been pointed out, he 
recognized two kinds of reasoning, viz., reasoning 
concerning ideas, and reasoning concerning matters 
of fact. "Relations or comparisons of ideas, . . . 
are the proper objects of [man's] intellectual facul- 
ties. ' ' But arguments of this nature ' ' lie too abstruse 
for the observation of [animals'] imperfect under- 
standings." Huxley did not seem to take sufficient 
account of language as a factor in the reasoning 
process. 

It may be remarked, in conclusion, that Hume's 
discussion on the reason of animals, except in so far 
as it prepared the way for the science of comparative 
psychology, is of exceedingly little value. It throws 
no light whatever on the question which is much 
agitated at the present day, viz., Do animals reason? 
The reasoning processes which Hume attributes to 
animals are merely instances of "association by con- 
tiguity." The real problem is, whether the mental 
processes of animals ever take the form of "associa- 
tion by similarity"?— a problem which, despite the 

i P. 469. 



PROBABILITY, NECESSITY, ANIMAL REASON. 215 

valuable and interesting work of Mills, Thorndike, 
and other enthusiastic investigators in this field, is 
still almost as far from a satisfactory solution as it 
ever was. 



CHAPTER X. 

THE IDEA OF MATERIAL SUBSTANCE, AND OF AN 
EXTERNAL WORLD. 

§ 38. The Idea of Material Substance.— Respecting 
the idea of material substance Berkeley stands in a 
relation to Locke similar to that in which Fichte 
stands to Kant. As Fichte rejected the ding-an-sich 
as the ground of phenomena, so did Berkeley the un- 
known something as the ground of material qualities. 
Hume merely followed in the track of Berkeley. 
His doctrine of substance, as presented in the Treatise, 
is well known. It is stated briefly in Part I, and is 
an immediate consequence of the fundamental prin- 
ciples of the philosophy of human nature. Since all 
ideas are derived from impressions ; and since impres- 
sions are of two kinds, sensation, and reflection; the 
idea of substance must be derived from an impression 
of sensation, or of reflection. If it be derived from 
an impression of sensation, it must be a color,, sound, 
taste, etc. ; and if it be derived from an impression 
of reflection, it must be a passion, or an emotion. 1 
Each of these alternatives is absurd. Hence, the idea 
of substance, if taken to be something other than that 
of a group of qualities, is a fiction. It is a complex 
idea resulting from the operation of the laws of asso- 
ciation, 2 and is "nothing but a collection of simple 
ideas," or a group of qualities with a particular name 
assigned to them. 3 

i P. 324. 2 p. 321. 3 p. 324. 

216 



MATERIAL SUBSTANCE AND EXTERNAL WORLD. 217 

In part IV, in accordance with his usual mode of 
procedure in the earlier work, Hume gives an account 
of the genesis of the idea of substance. 1 On observing 
the successive qualities of an object through a brief 
lapse of time, when the succession is smooth and 
gradual the mind is carried insensibly along by an 
easy transition, and does not perceive the change any 
more than it would did it contemplate a single un- 
changeable object. In this way arises the idea of 
identity. But when the smooth succession of quali- 
ties is hindered, either by a break in the sequence, or 
by a rapid change in the object, the natural progress 
of the thought is interrupted. Then there arises the 
idea of diversity. And as the ideas of identity and 
diversity are contrary to each other, the imagination, 
in order to solve the contradiction, feigns an unknown 
something which is supposed to remain invariably the 
same throughout the change of qualities. This un- 
known something is substance. It is a fiction postu- 
lated by the mind in order to unite the various quali- 
ties of objects or impressions, and is postulated ac- 
cording to natural laws. The fiction of an underlying 
substance, however, is wholly unnecessary, because 
qualities may exist by themselves. "Every quality 
being a distinct thing from another," says Hume, 2 
"may be conceived to exist apart, and may exist 
apart, not only from every other quality, but from 
that unintelligible chimera of a substance." Hence 
there is a twofold argument against the validity of 
the idea (1) It is unnecessary; (2) it is impossible. 

In the Inquiry there is no discussion of the idea of 
substance. As has already been mentioned, 8 the treat- 

1 Pp. 50G, 507. 2 P. 508. 3 Pp. 80, 81. 



218 hume's treatise and inquiry. 

ment of complex ideas— substances, modes, and rela- 
tions—is omitted. There are some incidental refer- 
ences, however., which have a bearing upon the idea 
of material substance, and which may be examined 
briefly. Hume asserts that the qualities of ' ' solidity, 
extension," and "motion," are "all complete in 
themselves"; 1 and that these qualities— the primary— 
are on the same basis as are the secondary. 2 Conse- 
quently, it may be concluded that the idea of sub- 
stance, if understood as anything different from the 
idea of a group of qualities, is unnecessary. Again, 
the criterion of the validity of ideas remains the same 
as it was in the Treatise. 3 Hence, it may be inferred 
that the idea is impossible. According to the logical 
standpoint of the Inquiry, therefore, the idea of sub- 
stance is both unnecessary and impossible, as it had 
been declared to be in the Treatise. In confirmation 
of this conclusion is the following passage from a 
letter of Hume to Henry Home in 1746 : 4 "As to the 
idea of substance, I must own, that as it has no access 
to the mind by any of our senses or feelings, it has 
always appeared to me to be nothing but an imaginary 
centre of union amongst the different and variable 
qualities that are to be found in every piece of 
matter. ' ' 

It may be inferred, therefore, that Hume's view of 
material substance was the same when he wrote the In- 
quiry as when he composed the Treatise. The prem- 
ises remain the same, the conclusion only is omitted. 
For this omission several explanations have been of- 

* P. 53. 2 Pp. 125-127. * Pp. 14, 16, 17, 52. 

*Tytler, Memoirs of H. H. of Karnes, I, p. 124; cf. Long, 
Ueber Hume's Lehre v. d. Ideen u. d. Substance, pp. 34, 36 n. 



PROBABILITY, NECESSITY, ANIMAL REASON. 219 

fered. It is a common opinion that, shortly after the 
publication of the Treatise, Hume became conscious 
that his principle of connection among ideas was very- 
defective. Thereupon his former account of fictitious 
ideas would appear to him to be unsatisfactory. And 
as he was unable to devise a more plausible process 
of their derivation, he would naturally avoid a discus- 
sion of the subject in the Inquiry. There does not 
appear to be much weight in this argument. Hume 
recognized that his principle of connection among 
ideas, when used to explain the fiction of self or of 
personal identity, was very defective, but not when 
used to explain the idea of cause and effect or of 
material substance. Selby-Bigge 1 asserts that "sub- 
stance is passed over," in the later work, "probably 
both from the difficulty of the subject, and because in 
the Enquiry Hume is not nearly so anxious to show 
that the fundamental popular conceptions are ficti- 
tious.' ' The former supposition appears to be 
groundless, inasmuch as the doctrine of substance is 
not any more difficult of treatment than is that of 
causation. But the latter statement undoubtedly 
contains an element of truth; for the Inquiry was 
written under different circumstances, and for a dif- 
ferent class of readers than was the Treatise. In the 
later work, Hume desired to present his theory of 
knowledge, or at least the more important parts of it, 
in a brief and popular manner. It is not surprising, 
therefore, that the discussion on substance was omit- 
ted. Moreover, the division of complex ideas into 
substances, modes, and relations was an inheritance 

1 Hume's Enquiries, p. xiii. 



220 hume's treatise and inquiry. 

from Locke. Hume was not so much dependent on 
Locke when he wrote the Inquiry as when he wrote 
the Treatise. 1 Consequently, the omission of this 
classification of ideas, and of the treatment of the 
particular topics included under it may have been 
due in part to that circumstance. 

§ 39. The Idea of an External World.— In the last 
section of Part II of the Treatise, Hume discusses the 
ideas of existence and external existence, as a prepara- 
tion for the examination of knowledge and probability. 
He states that the idea of existence is ' ' the very same 
with the idea of what we conceive to be existent," 2 
and concludes : 3 ' ' Since nothing is ever present to the 
mind but perceptions, and since all ideas are derived 
from something antecedently present to the mind; it 
follows, that it is impossible for us so much as to con- 
ceive or form an idea of any thing specifically dif- 
ferent from ideas and impressions." This discussion 
of external existence is only introductory. The full 
treatment of the subject is given in Part IV, where 
the question of the existence of an external world is 
dealt with under two heads: (1) The vulgar hypoth- 
esis; and (2) the philosophical. 

I. The Vulgar Hypothesis. The vulgar hypothesis 
of external existence is the assumption that sense per- 
ceptions are external material objects. " It is certain, ' ' 
says Hume, 4 "that almost all mankind, and even 
philosophers themselves, for the greater part of their 
lives, take their perceptions to be their only objects, 
and suppose, that the very being, which is intimately 
present to the mind, is the real body or material exist- 

i Cf. I, pp. 308, 342; IV, p. 17 n. 1. 

2 P. 370. 3 p. 371. 4 p. 495 . c f. p. 491. 



MATERIAL SUBSTANCE AND EXTERNAL WORLD. 221 

ence." And since it is vain to ask, "Whether there be 
body or not? as this is a point which must always be 
taken for granted, nature not having left it a matter 
of choice, the question which he raises now is, "What 
causes induce us to believe in the existence of body ? ' ' 
In answer, he professes to show: 1 (1) How the vulgar 
hypothesis of continued and distinct or independent 
existence arises; (2) why this kind of existence is 
attended with belief? Upon the elaborate process of 
derivation and explanation it is unnecessary to enter. 
It is sufficient to note the following characteristic 
features of the discussion in the Treatise: (1) "Every 
impression, external and internal, passions, affections, 
sensations, pains and pleasures, are originally on the 
same footing." 2 (2) The idea of continued and dis- 
tinct existence, or of the external existence of per- 
ceptions is derived neither from the senses, 3 nor from 
reason, 4 but from the imagination. 5 Objects have a 
certain coherence as they appear to the senses. And 
the imagination, "when set into any train of thinking, 
is apt to continue, even when its object fails it, and 
like a galley put in motion by the oars, carries on its 
course, without any new impulse." In this manner, 
from the constancy and coherence of perceptions 
arises the idea of their continued and distinct or inde- 
pendent existence. (3) Belief in the external exist- 
ence of perceptions arises through the effect upon the 
imagination of the force and vivacity of the successive 
imbling perceptions, in accordance with Hume's 
genera] theory. 7 

1 P. 478. ■ P. 480; cf. p. 371. 3 p p . 478-482. « P. 483. 
■ Pp. 184-495. ■ Pp. 496, 407. 7 Of. pp. 182, 183, above. 



222 hume's treatise and inquiry. 

In the first part of section xii of the Inquiry, there 
are a few references to the existence of an external 
world. The distinction between the vulgar hypothesis 
of external existence, and the philosophical, is not 
explicitly made in these terms ; but it is clear that the 
distinction which is here recognized, is the same as 
that made in the earlier wort. 1 Concerning the vul- 
gar hypothesis, Hume's position may be represented 
as follows: (1) The primary and secondary qualities 
of objects are on the same basis, and are only per- 
ceptions in the mind. 2 (2) All men, and even ani- 
mals., ' ' are carried, by a natural instinct or preposses- 
sion, to repose faith in their, senses/' and to suppose 
an external universe to exist; and "when men follow 
this blind and powerful instinct of nature, they al- 
ways suppose the very images, presented by the senses, 
to be the external objects." 3 (3) An explanation of 
belief is not given, but the doctrine of belief in the 
Inquiry is essentially the same as that in the Treatise, 4 
viz., belief consists in the force, vivacity, steadiness, 
etc., of an impression or idea. 5 Consequently, it may 
be concluded that, on the question of the vulgar hy- 
pothesis, the position of both works is practically the 
same. The only significant difference consists in 
omissions; the treatment in the earlier work being 
detailed and explicit, but in the later, brief, to a large 
extent indeed only implied. 

It may be observed that Brede professes to find, in 
the Inquiry, an important difference on this question. 
He asserts: 6 " [The vulgar hypothesis of an external 

1 P. 125. 2 pp. 124, 125. 3 P. 124. 

4 Cf. pp. 177-182, above. 5 p p . 40, 43. 

6 Der Unterschied d, Lehren H., pp. 47, 48. 



MATERIAL SUBSTANCE AND EXTERNAL WORLD. 223 

world] is here based solely on a supposed deception of 
the senses, an assumption which, in the Treatise, was 
directly rejected." The difference her.e pointed out 
is only one of the meaning of words. Hume is not 
precise in his use of language. He uses imagination 
in several different senses; — as contrasted with mem- 
ory, 1 as opposed to reason, 2 and yet as equivalent to 
reason or the understanding, 3 as synonymous with 
sense, 4 and as synonymous with nature or instinct. 5 
In the account, in the later work, he does not explicitly 
state that the vulgar hypothesis arises through an 
illusion of the senses, nor in any manner different 
from that in which he regarded it as originating in 
the earlier. He says it arises from "a natural in- 
stinct." In the Treatise he said it arises from na- 
ture, instinct, or imagination. 7 True, in the Inquiry, 
Hume admits that, on this topic, there is a conflict 
between the senses and reason, as if to imply that the 
vulgar hypothesis is derived from the senses, and the 
philosophical hypothesis from the reason. 8 But in a 
similar manner, in the earlier work, he admitted the 
existence of a conflict, on the same subject. 9 Of 
course it is admitted that Hume, in the Inquiry, seems 
to regard the idea of external existence as being de- 
rived through the senses. 10 But it must not be over- 
Looked that, in the Treatise, he uses "senses" as a 
convenient term for imagination, or the principles 
that give rise to the vulgar hypothesis. Thus he as- 
serts: 11 "There is a direct and total opposition betwixt 

i I, p. 317. * I, pp. 41G n., 502. 3 I, p. 547; cf. p. 505. 
* I, p. 504. s i } p p# 4 78) 501, 502. e Pp. 124, 127. 

7 Pp. 478, 501, 502. s Pp. 125, 127. 9 P. 504. i° P. 124. 
" P. 510. 



224 hume's treatise and inquiry. 

our reason and our senses ; or, more properly speaking, 
betwixt those conclusions we form from cause and 
effect, and those that persuade us of the continued 
and independent existence of body." It is obvious, 
therefore, that since no real diversity of view exists 
on this question, the briefer treatment in the later 
work is the cause of the apparent diversity of state- 
ment. 

II. The Philosophical Hypothesis. The philosoph- 
ical hypothesis of an external world is the assumption 
of "the double existence of perceptions and objects," 
of perceptions in the mind, and of external objects 
corresponding to them. 1 According to the account 
in the Treatise, the philosophical hypothesis arises in 
the following manner: after arriving at the vulgar 
hypothesis, and acquiring a belief that perceptions 
are external objects, if one makes a few experiments, 
or reasons about the matter, one immediately perceives 
that the existence of perceptions is interrupted, and 
that "the doctrine of the independent existence" of 
sensible perceptions "is contrary to the plainest ex- 
perience." 2 Then, in order, to solve the contradic- 
tion, the philosophers invent the hypothesis of "the 
double existence of perceptions and objects," and 
suppose the former "to be interrupted, and perish- 
ing," but the latter "to be uninterrupted, and to 
observe a continued existence and identity." 3 The 
philosophical hypothesis, however, in the author's 
estimation, "is only a palliative remedy," and "con- 
tains all the difficulties of the vulgar system, as well 
as some others that are peculiar to itself." It has 
"no primary recommendation either to reason or the 

i I, p. 499. 2 p. 498. 3 p. 499. 



MATERIAL SUBSTANCE AND EXTERNAL WORLD. 225 

imagination," but "acquires all its influence on the 
imagination" from the vulgar hypothesis. 1 And 
Hume 2 concludes: "This skeptical doubt, both with 
respect to reason and. the senses, is a malady, which 
can never be radically cured, . . . Carelessness and 
inattention alone can afford us any remedy." On 
these qualities of mind he relies with a degree of 
assurance not surpassed by the confidence placed in 
the principles of common sense by his illustrious 
countrymen of the Scottish School. 3 

In addition to the argument in the second section, 
Hume claims to show, in the fourth, that if the funda- 
mental principle of modern philosophy— viz., the 
subjectivity of the secondary qualities of objects,— 
be admitted, there is no ground for attributing ob- 
jectivity to the primary qualities, and consequently, 
no possibility of arriving at a knowledge of external 
existence. Thus he asserts: 4 "I believe many objec- 
tions might be made to this system [modern philos- 
ophy] : But at present I shall confine myself to one, 
which is in my opinion very decisive. I assert, that 
instead of explaining the operations of external ob- 
jects by its means, we utterly annihilate all these 
objects, and reduce ourselves to the opinion of the 
most extravagant skepticism concerning them. If 
colors, sounds, tastes, and smells be merely perceptions 
[and this he has repeatedly affirmed], 5 nothing we 
can conceive is possessed of a real, continued, and 
independent existence ; not even motion, extension and 
solidity, which are the primary qualities chiefly in- 
sisted on." Then he resolves the primary qualities 

i Pp. 499, 500. 2 p. 505. 3 cf. Ibid. * P. 513. 

6 Pp. 371, 481, 482, 511, 512, 52G. 
15 



226 hume's treatise and inquiry. 

into secondary : ' i The idea of motion depends on that 
of extension, and the idea of extension on that of 
solidity." Solidity is inconceivable alone, because it 
depends on other secondary qualities. "And upon 
the whole," says Hume, 1 "[we] must conclude, that 
after the exclusion of colors, sounds, heat and cold 
from the rank of external existences, there remains 
nothing, which can afford us a just and constituent 
idea of body." In Part IV, he also refers to Part II, 
and claims that there he has already shown "the no- 
tion of external existence, when taken for something 
specifically different from our perceptions," to be 
"an absurdity." 2 

In the twelfth section of the Inquiry, Hume gives 
a brief account of the philosophical hypothesis of ex- 
ternal existence. After referring to the universal 
belief of mankind in the existence of an external 
world, a belief that "the very images, presented by 
the senses," are "the external objects/' he proceeds: 3 
"But this universal and primary opinion of all men 
is soon destroyed by the slightest philosophy, which 
teaches us, that nothing can ever be present to the 
mind but an image or perception, and that the senses 
are only the inlets, through which these images are 
conveyed, without being able to produce any imme- 
diate intercourse between the mind and the object. 
The table, which we see, seems to diminish, as we re- 
move farther from it : But the real table, which exists 
independently of us, suffers no alteration: It was, 
therefore, nothing but its image, which was present 
to the mind. These are the obvious dictates of reason ; 
and no man, who reflects, ever doubted, that the ex- 

i P. 514. 2 p. 479. s Pp. 124, 125. 



MATERIAL SUBSTANCE AND EXTERNAL WORLD. 227 

istences, which we consider, when we say, this horse 
and that tree, are nothing but perceptions in the mind, 
and fleeting copies or representations of other exist- 
ences, which remain uniform and independent." But 
what existences are those that are thought to remain 
"uniform and independent' '? Hume replies: 1 "So 
far, then, are we necessitated by reasoning to con- 
tradict or depart from the primary instincts of nature, 
and to embrace a new system with regard to the evi- 
dence of our senses. But here philosophy finds her- 
self extremely embarrassed, when she would justify 
this new system, and obviate the cavils and objections 
of the skeptics. ... To justify this pretended philo- 
sophical system, by a chain of clear and convincing 
arguments, or even any appearance of argument, ex- 
ceeds the power of all human capacity. " 

In the Inquiry also, the distinction between the 
primary and secondary qualities of objects is referred 
to in a manner similar to that in the Treatise. "It 
is universally allowed by modern inquirers,' ' says 
Hume, 2 "that all the sensible qualities of objects, such 
as hard, soft, hot, cold, white, black, etc., are merely 
secondary, and exist not in the objects themselves, but 
are perceptions of the mind, without any external 
archetype or. model, which they represent. If this be 
allowed, with regard to secondary qualities, it must 
also follow, with regard to the supposed primary 
qualities of extension and solidity; nor can the latter 
be any more entitled to that denomination than the 
former. The idea of extension is entirely acquired 
from the senses of sight and feeling; and if all the 
qualities, perceived by the senses, be in the mind 

■ P. 126. 2 Pp. 120, 127. 



228 hume's treatise and inquiry. 

[and this is what he maintains], 1 not in the object, 
the same conclusion must reach the idea of extension, 
which is wholly dependent on the sensible ideas or, 
the ideas of secondary qualities. Nothing can save 
us from this conclusion, but the asserting, that the 
ideas of those primary qualities are attained by Ab- 
straction; an opinion, which, if we examine it accu- 
rately, we shall find to be unintelligible, and even 
absurd. ' ' 

On the question of the philosophical hypothesis of 
external existence, therefore, the standpoint of both 
works is identical. As in almost every other instance, 
however, the mode of treatment is different. The 
account in the Inquiry is so brief that one learns its 
full significance only by reading it in connection with 
the exposition in the Treatise. The tone also is less 
dogmatic, and the manner of expression more careful. 
These differences ar.e only such as one would natu- 
rally expect, if one takes into account Hume's tem- 
perament, and the circumstances under which the 
respective books were written. 2 

§ 40. Conclusion.— The chief points in the chapter 
may now be brought together. 

1. The Idea of Material Substance. In the Treatise, 
Hume professed to show that the idea of material 
substance can be derived neither from sensation, nor 
from reflection. It is, therefore a fiction, produced 
by the imagination. The idea of identity arises on 
viewing a series of successive resembling perceptions 
of the same object. This idea, when the series is 
broken, gives place to that of diversity. Then, to 

i Cf. pp. 13-17, 61, 124, 125, 126. 
2 Cf. Burton, Life, I, pp. 63, 98. 



MATERIAL SUBSTANCE AND EXTERNAL WORLD. 229 

solve the contradiction, the imagination posits the 
idea of substance, as the ground of union for the 
different perceptions. In a letter to Home, in 1746, 
Hume expressed the same view as that in the Treatise. 
Consequently, it may be concluded that his position 
was unchanged when he wrote the Inquiry. In the 
later work, the discussion is omitted. The cause for 
this omission is not positively known, but was prob- 
ably desire for brevity, for simplicity, or for pop- 
ularity. 

2. The Idea of an External World. According to 
the account in the Treatise, the mind knows only per- 
ceptions. 1 To these perceptions is attributed an in- 
dependent existence, through the influence of imag- 
ination or natural instinct. 2 Reflection shows that 
this belief is contrary to reason. 3 To solve the con- 
tradiction the mind invents the hypothesis of "the 
double existence of perceptions and objects. " 4 But 
this assumption is contrary to natural instinct, and 
besides, cannot be justified by reason. 5 "This philo- 
sophical system/' Hume asserts/ "is the monstrous 
offspring of two principles, which are contrary to 
each other, which are both at once embraced by the 
mind, and which are unable mutually to destroy each 
other." Then with his accustomed frankness, he gives 
expression to his own feeling in the following words: 7 
"Having thus given an account of all the systems 

■ I, pp. 371, 483, 487, 501, 518; IV, pp. 01, 124, 12G. 

2 I, pp. 478, 484, 491, 493, 495, 501; IV, pp. 124, 125. 

3 I, pp. 498, 501, 504; IV, pp. 124, 125, 127. 

* I, pp. 499, 501, 502; IV, pp. 125-127. 
5 Ibid. 

* I, ]). 502; of. IV, ]>. 126. 

* I, p. 504; cf. IV, p. 12G. 



230 hume's treatise and inquiry. 

both popular and philosophical, with regard to ex- 
ternal existences, I cannot forbear giving vent to a 
certain sentiment, which arises upon reviewing those 
systems. I began this subject with premising, that 
we ought to have an implicit faith in our senses, and 
that this would be the conclusion, I should draw from 
the whole of my reasoning. But to be ingenuous, I 
feel myself at present of a quite contrary sentiment, 
and am more inclined to repose no faith at all in my 
senses, or rather imagination, than to place in it such 
an implicit confidence." 

The position of the Inquiry on the question of the 
existence of an external world is similar to that of the 
Treatise, 1 except in one respect. In the earlier work, 
when Hume professes to have shown how belief in 
external existence arises from the force and vivacity 
of resembling perceptions, and that the mind knows 
nothing specifically different from perceptions, he 
appears as the expounder and advocate of a system of 
skepticism. In the later, work, he omits an account 
of the derivation of belief in external existence, and 
appears, not as the exponent of a system, but rather 
as a dialectitian. In the Inquiry, he is a critic of the 
prevailing systems; in the Treatise, he is not merely 
a critic, but also the expounder of a new system. 
While this constructive element gives the earlier work 
an air of positiveness ; from another point of view, it 
only serves to make the skepticism more pronounced. 
Hence, it is easy for any one to put forward the claim 
that either book is more negative, or is more positive 
than the other. It is most probable, however, that 

1 Cf. Bain, Mental and Moral Science, p. 205; Burton, Life, 
I, pp. 274, 33T. 



MATERIAL SUBSTANCE AND EXTERNAL WORLD. 231 

the omissions, in the Inquiry, were due entirely to 
adventitious circumstances, and not to any real change 
of view on the part of the author. 

Hume's philosophical position on the question of 
the existence of an external world is still a matter of 
dispute. On the one hand, it is universally admitted 
that he affirmed a belief in external existence ; and on 
the other, it is generally recognized that he denied 
the possibility of any real knowledge of external exist- 
ence, as something different from perceptions. But 
between these two extremes lie many intermediate 
views. Jodl 1 states that, according to Hume, nothing 
remains of the ideas of matter and external existence 
but, at most, an unknown, inexplicable something as 
the cause of perceptions, and which the skeptic will 
not envy any one. Windelband 2 affirms that the ex- 
istence of a corporeal world is to be assumed as at 
most only probable. Falckenberg 3 declares that Hume 
does not follow Berkeley to the extent of denying ex- 
ternal reality. Erdmann asserts: 4 "Hume never 
doubted, what was regarded beyond everything else 
as doubtful by the skeptics of antiquity, the existence 
of what we perceive.' ' Brown 5 holds that, on this 
question, Hume and Reid are in accord. One cannot 
prove by reason the existence of an external world, 
but one believes. Hume emphasizes the first position, 
and Reid the second; this is all the difference be- 

1 Leben unci Phil. D. II., p. 75. 

" Qeeeh. d. n. Phil., I, p. 319. 

3 History of Modern Philosophy, p. 221. 

* History of Philosophy, II, p. 130. 

5 Lectures on the Philosopliy of Mind, II, p. 89. 



232 hume's treatise and inquiry. 

tween them. Webb states: 1 "So far is Hume from 
dogmatically denying the existence of an external 
world in external space that he systematically assumes 
it." And Reid declares: 2 "When we find Bishop 
Berkeley and Mr. Hume, the acutest metaphysicians 
of the age, maintaining that there is no such thing as 
matter in the universe— . . . when we find the last 
maintaining that there is neither body nor mind— 
... we may be apt to think the whole to be only a 
dream of fanciful men, who have entangled themselves 
in cobwebs spun out of their own brain. ' ' 

It is natural to expect that a question on which 
there is so much diversity of opinion is extremely 
difficult accurately to determine. Such is indeed the 
case. And what the opinion of any individual writer 
may be, with regard to the problem, seems to be a 
matter of extremely little moment ; for it is reasonable 
to suppose that, in the future, as in the past, among 
Hume's interpreters, sentiment rather than reason 
will give the casting vote on this question. Such con- 
sideration, however, will never deter the philosopher 
from offering a new solution. Hume's position on 
the question of the existence of an external world 
appears to be the following: Accepting the existence 
of perceptions— a form of reality which no one ever 
doubted,— he professed to explain, both according to 
the vulgar hypothesis, and according to the philo- 
sophical, how, through certain qualities of the imag- 
ination, belief in an external world arises. But he 

1 Veil of Isis, p. 121 ; cf. Hunt, Contemporary Revieiv, Vol. 
XI, p. 83; Papillon, Histoire de la Philosophie Moderne, II, 
p. 19; Uhl, Humes Stellung in d. englischen Phil., I, p. 13; 
Bain, Mental and Moral Science, p. 207. 

2 Works, I, p. 242. 



MATERIAL SUBSTANCE AND EXTERNAL WORLD. 233 

also claimed to show that both these beliefs are irra- 
tional and unjustifiable; the first being contrary to 
reason, the second contrary to natural instinct, and 
each contradictory to the other. Nevertheless, he as- 
serted that the matter has not been left to choice, that 
the mind, in accordance with the fundamental prin- 
ciples of human nature, still continues to reason about 
these contradictory alternatives, and to believe in the 
existence of an external world. Such existence, how- 
ever, lies outside the sphere of knowledge, and hence 
is both unknown and unknowable. The final outcome, 
therefore, of Hume's reasoning on this question is 
philosophical or theoretical skepticism. But our phi- 
losopher is not a dogmatist; whether there is an ex- 
ternal world or not does not trouble him in the least. 
Nature is able enough to take care of herself; and 
nature necessitates an irresistable belief in external 
existence. This is sufficient for. the needs of every- 
day life. Hence, actually, he is a positivist. 

Theoretically, therefore, Hume is a skeptic; prac- 
tically, he is a realist ; and actually, he is a positivist. 
Consequently, it is not surprising that, notwithstand- 
ing his positivism and skepticism, he frequently im- 
plies, both in the Treatise and in the Inquiry, the 
existence of an external world as unhesitatingly as 
if he were a philosopher of the Scottish School. 1 The 
concluding passage of his treatment of the question is 
characteristic of the author, and significant of his 
true position. "Carelessness and inattention alone/' 
he says, 2 can afford us any remedy [against the 
malady of skeptical doubt]. For this reason I rely 

" Of. I, pp. 317, 342, 4G1, 4G2, 540; IV, pp. 23, 25, 28, 46, 47. 
i I, p. 505. 



234 hume's treatise and inquiry. 

entirely upon them ; and take it for granted, whatever 
may be the reader's opinion at this present moment, 
that an hour hence he will be persuaded there is both 
an external and internal world ; and going upon that 
supposition, I intend to examine some general systems 
both ancient and modern, . . . before I proceed to 
a more particular inquiry concerning our impres- 
sions. ' ' 

The foundation stone of metaphysics has often be- 
come the Achilles' heel. Such it became for Hume. 
The vulnerable point in his philosophical system, the 
source of his gravest errors as well as the cause of his 
greatest difficulties, is his inadequate conception of 
the self. He failed to realize that self-knowledge is 
knowledge of something permanent and substantial. 
This knowledge is the key to all knowledge, since the 
microcosm is an organic part of the macrocosm. As 
there is real knowledge of the self, so real knowledge 
is inherently possible of all other things, in so far as 
they partake of the nature of self. The transition 
from knowledge of the self to knowledge of other 
selves, and even to knowledge of external things, is 
clearly intelligible as well as perfectly natural. 



CHAPTER XI. 

SPIRITUAL SUBSTANCE, THE SELF, AND PERSONAL 
IDENTITY. 

§ 41. The Idea of Spiritual Substance.— The ideas 
of spiritual substance, self, and personal identity are 
so closely related to one another, that it is extremely 
difficult to discuss them separately. It seems that, 
for Hume, spiritual substance is equivalent to mind 
in general, self is the concrete or individual mind, and 
personal identity is a quality or supposed quality of 
self, viz., its permanence and invariability. "With this 
explanation, the ideas of spiritual substance, self, and 
personal identity will be treated in their order. 

Sidney Smith once humorously remarked: "Bishop 
Berkeley destroyed the world in one volume octavo, 
and nothing remained after his time but mind, which 
experienced a similar, fate from Mr. Hume in 1739." 
Hume's criticism of spiritual substance is merely an 
application of Berkeley's principle regarding material 
substance. As Berkeley showed that Locke's idea of 
material substance, according to his own presupposi- 
tions, was a fiction, so Hume showed, in like manner, 
that his idea of spiritual substance is a fiction also. 
The doctrine of spiritual substance, as explained in 
the Treatise, is strictly analogous to that of material 
substance. There is no impression of substance, 
either of material,, or of spiritual; consequently, there 
is no valid idea either of material, or of spiritual 

235 



236 hume's treatise and inquiry. 

substance. 1 An idea of spiritual substance is not 
needed in the philosophy of human nature, any more 
than is required an idea of material substance. For. 
thus Hume reasons: 2 "Whatever is clearly conceived 
may exist; and whatever is clearly conceived, after 
any manner, may exist after the same manner. This 
is one principle, which has been already acknowl- 
edged. Again, every thing, which is different, is 
distinguishable, and every thing which is distinguish- 
able, is separable by the imagination. This is an- 
other, principle. My conclusion from both is, that 
since all our perceptions are different from each other, 
and from every thing else in the universe, they are 
also distinct and separable, and may be considered as 
separately existent, and may exist separately, and 
have no need of any thing else to support their exist- 
ence. ' ' The genesis of the fictitious idea of spiritual 
substance Hume likewise attempts to explain in the 
same way as he explained the origin of the idea of 
material substance. 3 

In the Inquiry, there is no treatment of spiritual 
substance. Hume's last word on this subject is in 
the appendix. Here spiritual substance and self are 
treated together, as if they meant the same thing; 
otherwise, the import of the discussion is similar to 
that of the exposition in the Treatise. Hume re- 
marks: 4 "Philosophers begin to be reconciled to the 
principle, that we have no idea of external substance, 
distinct from the idea of particular qualities. This 
must pave the way for a like principle with regard to 

i P. 517. 2 p. 518. 

3 Pp. 535, 536. ^ l 9 p. 559. 



237 

the niind, that we have no notion of it, distinct from 
the particular perceptions." Again, he says: 1 "When 
we talk of self or substance, we must have an idea 
annexed to these terms, otherwise they are altogether 
unintelligible. Every idea is derived from precedent 
impressions; and we have no impression of self or 
substance, as something simple or individual. We 
have, therefore, no idea of them in that sense. " 
Finally, the idea of spiritual substance is not neces- 
sary; for he asserts: 2 "Whatever is distinct, is dis- 
tinguishable; and whatever is distinguishable, is sep- 
arable by the thought or imagination. All perceptions 
are distinct. They are, therefore, distinguishable, and 
separable, and may be conceived as separately existent, 
and may exist separately, without any contradiction 
or absurdity." It is manifest that the doctrine of 
spiritual substance is exactly the same in the appendix 
as in the Treatise. Consequently, there is a strong 
probability that when Hume wrote the Inquiry he had 
not changed his view, in any important respect, upon 
this question. 3 The reasons for omitting the discus- 
sion, in the later work, were in large measure similar 
to those for omitting a specific treatment of material 
substance. 4 

§ 42. The Idea of Self.— The tacit implication of 
the existence of the self Hume, no doubt, found help- 
ful when explaining belief, both in the relation of 
cause and effect, and in the existence of an external 

1 1, p. .i.is. 2 md. 

• Cf. Bain, Mental and Moral Science, p. 205; Windelband, 
Gesch. <L v. Phil., p. 824. 
*('/". pp. 208-209, above. 



238 hume's treatise and inquiry. 

world. But having explained these doctrines, at 
least to his own satisfaction, he was in a position, at 
the end of his system, to abolish the idea of self as a 
fiction, like the many preceding ones. Again he asks, 
from what impression can the idea of self be derived ? 
And since he regarded a numerically identical and 
permanent self as something that continues "invari- 
ably the same" throughout the whole course of one's 
life— a grain of sand, as it were, or an atom of pure 
being,— an impression of the self must also be con- 
stant and invariable. But "there is no impression 
constant and invariable." Consequently, there is no 
impression of self as something that remains the same 
throughout one 's life. 1 What then is the self ? ' ' For 
my part," says Hume, 2 "when I enter most intimately 
into what I call myself, I always stumble on some 
particular perception or other, of heat or cold, light 
or shade, love or hatred, pain or pleasure. I never 
catch myself at any time without a perception, and 
never can observe any thing but a perception. " " The 
mind is a kind of theatre, ' ' he continues, ' ' where sev- 
eral perceptions successively make their appearance; 
pass, re-pass, glide away, and mingle in an infinite 
variety of postures and situations. There is properly 
no simplicity in it at one time, nor, identity in differ- 
ent; whatever natural propension we may have to 
imagine that simplicity and identity. The compar- 
ison of the theatre must not mislead us. They are 
the successive perceptions only, that constitute the 
mind; nor have we the most distant notion of the 
place, where these scenes are represented, or of the 
materials, of which it is composed. ' ' 
i P. 533. 2 p. 534. C f. pp. 541, 542. 



SPIRITUAL SUBSTANCE, PERSONAL IDENTITY. 239 

After thus professing to prove that the idea of self 
is invalid, Hume undertakes to explain the genesis of 
the fiction. The explanation is exactly similar, to that 
of the fiction of spiritual substance. Successive per- 
ceptions, by means of a quality of the imagination, 
are involuntarily regarded as constituting a continued 
existence. But the continued existence is interrupted 
in the course of every-day experience. Then, to solve 
the contradiction, the mind feigns the idea of self as 
something permanent and invariable, a fictitious 
ground of union for the ever-changing ideas of which 
the actual self is composed. 1 

In the appendix, the idea of self is not distinguished 
from that of spiritual substance; as already men- 
tioned, 2 both are there treated together. And as no 
explicit reference is made in the Inquiry to either 
topic, further discussion of the subject is for the 
present unnecessary. We shall return to this ques- 
tion in a following section. 3 

§ 43. The Idea of Personal Identity.— It the self 
is "nothing but a bundle or collection of different 
perceptions, which succeed each other with an incon- 
ceivable rapidity, and are in a perpetual flux and 
movement/' 4 it may be asked, How does the idea of 
personal identity arise? Personal identity, Hume ac- 
knowledges, in the Treatise has become a great ques- 
tion in philosophy, "especially of late years in Eng- 
land." He thinks it is to be explained in the same 
manner as the identity of plants, houses, ships, or. 
rivers."' Consequently, the identity which is com- 
monly ascribed to "the mind of man" is only "a 

i Pp. 535, 536 j cf. II, pp. 74, 142. 2 P. 2: ? ,n. 

3 Pp. 242-266. > Pp. 534. *Pp. 638, 539. 



240 hume's treatise and inquiry. 

fictitious one." "It is still true," he says, 1 "that 
every distinct perception, ... is a distinct exist- 
ence, and is different, and distinguishable, and sep- 
arable from every other perception. . . . But, as, 
notwithstanding this distinction and separability we 
suppose the whole train of perceptions to be united 
by identity, a question naturally arises concerning 
this relation of identity ; whether it be something that 
really binds our several perceptions together, or only 
associates their ideas in the imagination. ' ' This mat- 
ter is easily decided by reference to the theory of 
cause and effect. "For from thence it evidently 
follows," continues Hume, 2 "that identity is nothing 
really belonging to these different perceptions, and 
uniting them together ; but is merely a quality, which 
we attribute to them, because of the union of their 
ideas in the imagination, when we reflect upon them." 
These qualities of union are the relations of resem- 
blance and causation. 3 

The idea of personal identity, like those of self and 
spiritual substance, is not dealt with in the Inquiry. 
Omitting an incidental reference in the Dialogues, 4 
this subject received final treatment in the appendix. 
The account given here has been justly characterized 5 
as one of those comprehensive reviews of the signifi- 
cance and the difficulties of Hume's empirical theory 
of cognition, which mark the rare acuteness of his 
intellect. In this reconsideration, Hume confesses 6 
that, "upon a more strict review of the section con- 
cerning personal identity," he finds himself involved 
in "such a labyrinth," that he knows neither "how 

i P. 540. 2 Ibid. 3 P. 541. * II, p. 406. 

5 Adamson, Ency. Brit., art. Hume, p. 354. 6 I, p. 558. 



SPIRITUAL SUBSTANCE, PERSONAL IDENTITY. 241 

to correct" his former opinions, nor "how to render 
them consistent. ' ' He then restates the arguments 
that induced him to deny "the strict and proper iden- 
tity and simplicity of a self or thinking being." 
These arguments are similar to those advanced previ- 
ously in the Treatise. After this restatement, how- 
ever, Hume brings forward an objection which did not 
appear in the earlier work. This objection is to the 
effect, that he is now unable satisfactorily to explain 
the principle of connection among perceptions. 
"Having thus loosened all our particular percep- 
tions," he says, 1 "when I proceed to explain the 
principle of connection, which binds them together, 
and makes us attribute to them a real simplicity and 
identity; I am sensible, that my account is very de- 
fective, and that nothing but the seeming evidence of 
the precedent reasonings could have induced me to 
receive it." But "the seeming evidence of the pre- 
cedent reasonings"— that is, of the reasoning con- 
cerning the ideas of substance and necessary connec- 
tion—is so clear that he is compelled to accept it also. 
Hence, he concludes as follows: 2 "In short there are 
two principles, which I cannot render consistent ; nor 
is it in my power to renounce either of them, viz., 
that all our distinct perceptions are distinct existences, 
and that the mind never perceives any real connection 
among distinct existences. Did our perceptions either 
inhere in something simple and individual, or did the 
mind perceive any real connection among them, there 
would be no difficulty in the case. For my part, I 
must plead the privilege of a skeptic, and confess, that 
1 I, p. 559. 2 Ih j dt 

16 



242 hume's treatise and inquiry. 

this difficulty is too hard for my understanding. I 
pretend not, however, to pronounce it absolutely in- 
superable. Others, perhaps, or myself, upon more 
mature reflections, may discover some hypothesis, that 
will reconcile these contradictions." 

Hume did not return to the question of personal 
identity. In the Inquiry, he still advocates the funda- 
mental principle, that " all our distinct perceptions are 
distinct existences," 1 and maintains that "the mind 
never perceives any real connection among distinct 
existences." 2 There is no reason to suppose, there- 
fore, that he was ever able to reconcile the contradic- 
tion of which he speaks. And neither is there any 
ground for thinking that this standing contradiction 
modified to any appreciable extent, either the doctrine 
or the contents of the Inquiry. This is not the view, 
however, which is generally held by Hume's inter- 
preters. Some have professed to find in the confes- 
sion in the appendix a key to the solution of many 
difficulties regarding the meaning and position of the 
later work— an explanation of many omissions, and a 
ground for many apparent changes of doctrine. The 
question is an important one ; but unhappily, one that 
does not admit of an easy answer. In fact, Hume's 
doctrine of the self, in the Inquiry, is generally recog- 
nized as being the most perplexing problem in the 
whole work. Hence, we devote to the consideration 
of this subject an additional section. 

§ 44. The Relation of the Treatise to the Inquiry 
on the Doctrine of Self and Personal Identity.— 

i Pp. 10, 27, 53, 61, 124, 125. 
2 Pp. 27, 52, 61, 75. 



SPIRITUAL SUBSTANCE, PERSONAL IDENTITY. 243 

Brede 1 and Grimm 2 are among the latest, as well as 
the ablest representatives of the theory that Hume, 
when he wrote the Inquiry, had become convinced of 
the existence of a real self and a real personal iden- 
tity ; and that this change of view had a marked effect 
upon the briefer exposition of his system. As there 
are no direct, and only a few indirect references to 
this question in the later work, the reasoning must 
be largely of the nature of probability. In support 
of Brede and Grimm's position 3 several arguments are 
adduced, which may be summarized in the following 
propositions:— (1) In the Treatise, Hume professed 
to explain the fiction, as well as to refute the doc- 
trines, of self and personal identity. (2) The expla- 
nation of these fictions is analogous to that of the 
fictitious idea of substance, and that of the assumption 
of external existence. (3) In the appendix, it is ac- 
knowledged, not only that the explanation given in the 
Treatise of the fiction of personal identity is "very 
defective, ' ' but also that Hume is now unable to give 
a derivation of this idea. (4) For these causes, the 
explanation of the fictitious ideas of substance, self, 
and personal identity— in fact, all explicit treatment 
of these subjects,— is omitted in the Inquiry. (5) 
For similar reasons, the assumption of the existence 
of an external world is attributed, in the later work, 
to an illusion of the senses ; and not, as in the Treatise, 
to a fiction of the imagination. (6) Since Hume, in 

1 Dcr Vntcrschicd d. Lchrcn H., pp. 4G-49. 

2 Zur Oesch. d. Erkenntnisproblems, pp. 575-577, 5S0-585. 

3 It may be observed that Grimm's position is not quite so 
positive as La that of Brede. At times he Beems to hold that 
Eume has merely abandoned the doctrine of the self, as ex- 
pounded in the Treatise, without adopting the view of a real 
permanent self, as Brede claims. 



244 hume's treatise and inquiry. 

the appendix, acknowledged himself unable to explain 
the fiction of personal identity, and yet, in the In- 
quiry, made fr.equent use of the ideas of self and self- 
consciousness, he must, when he wrote the later work, 
have been convinced of the real existence of the self 
and personal identity, and thus have renounced the 
doctrine of the Treatise. (7) In confirmation of this 
conclusion are the facts: (a) Hume, in the Inquiry, 
speaks repeatedly of impressions and ideas being 
present to the mind, without ever saying that the mind 
is this sum of perceptions; (b) the Inquiry, he asserts, 
in the advertisement to the posthumous and authori- 
tative edition of his works, and not the Treatise, rep- 
resents his true position. (8) Finally, in the section 
on "A particular Providence and a future State," 
it is unaccountable why Hume did not bring forward 
his former doctrine of the self as an argument against 
belief in the immortality of the soul, except on the 
ground that, in the meantime, he had abandoned that 
doctrine. 

Yet another argument, one hitherto overlooked, may 
be added to those of Brede and Grimm to complete 
the reasoning. Henry Home endeavored to persuade 
Hume not to publish the Inquiry; but in vain. 1 A 
few years later, in 1751, Home published his Essays 
on the Principles of Morality and Natural Religion. 
One of the main objects of this work was to counter- 
act the influence of Hume's speculative writings. 2 
Before publishing, Home apparently sent the manu- 
script to his friend for perusal. The essay on "Per- 
sonal Identity" begins as follows: 3 "Had we no orig- 

i Tytler, Memoirs of H. E. of Karnes, I, p. 129. 

*Cf. Ibid., p. 131. 3 p. 231. 






SPIRITUAL SUBSTANCE, PERSONAL IDENTITY. 245 

inal impressions but those of the external senses, 
according to the author of the treatise of human 
nature, we never could have any consciousness of 
self ; because such consciousness cannot arise from 
any external sense. . . . Neither could there be any 
idea of personal identity. For a man, cannot con- 
sider himself to be the same person, in different cir- 
cumstances, when he has no idea or consciousness of 
himself at all." Home then proceeds to show how, 
according to his theory, the ideas of self and personal 
identity arise from an internal impression. 1 In 1746, 
Hume wrote to Home, regarding this essay: 2 "I like 
exceedingly your method of explaining personal iden- 
tity, as being more satisfactory than any thing that 
had ever occurred to me." It might reasonably be 
supposed, therefore, that when Hume, in 1748, pub- 
lished the Inquiry, he had adopted the position of 
Home on the questions of self and personal identity— 
or, at least, had relinquished the doctrines of the 
Treatise; and it might also be thought that Home's 
treatment of personal identity, in connection with 
Hume's recognition in the appendix of the contradic- 
tion in his fundamental principles, had played an 
important part in determining the standpoint and 
contents of the later work. The argument, however, 
is not so formidable as it appears to be; moreover, 
there are some considerations on the other side of the 
question, which will, perhaps, give occasion to reverse 
the foregoing conclusion. 

Propositions (1), (2), and (3) are statements of 
fad that arc admitted. Proposition (4) is admitted, 

i Pp. 232, 233. 

1 Tytk-r, Memoirs of II. II. of Kamcs, I, p. 124. 



246 hume's treatise and inquiry. 

in the main. Hume's recognition, in the appendix, 
that he could not explain the fiction of personal iden- 
tity is a valid reason— although probably not the only 
one, and perhaps not the chief one,— for the omission, 
in the Inquiry, of a treatment of the ideas of spiritual 
substance, self, and personal identity. Debate begins 
with proposition (5). Regarding this part of the 
argument it may be remarked, that even if the truth 
of the conclusion be granted, the validity of the infer- 
ence is not established. For since Hume still believes 
that his method of explaining fictions, by means of the 
imagination, is valid, and satisfactory when applied 
to the idea of cause and effect— as he certainly does 
in the Inquiry,— there is no ground to suppose that 
he would hold the same method to be invalid or un- 
satisfactory when applied to the ideas of material 
substance and external existence; the three cases, on 
his principles, are exactly parallel. But it has al- 
ready been shown, 1 that the conclusion is not true. 
For Hume, in the briefer work, looks upon "the vulgar 
hypothesis/' or the assumption of the existence of an 
external world, as arising, not from the senses, but 
from ' ' a natural instinct, ' ' and implies an explanation 
of it similar to that in the Treatise. Consequently, 
the argument in the fifth proposition is utterly with- 
out foundation. The position adopted in proposition 
(6) cannot be sustained. It is of course evident that 
Hume's confession, in the appendix, that he could not 
explain the fiction of personal identity is not a suffi- 
cient reason for assuming that his doctrine of the self 
was changed, when he wrote the Inquiry ; particularly, 
since it had remained unchanged when the confession 
*Pp. 211, 212, above. 



SPIRITUAL SUBSTANCE, PERSONAL IDENTITY. 247 

was made. When Hume acknowledged that his ac- 
count of personal identity was "a labyrinth" of in- 
accuracies and inconsistencies, he did not acknowledge 
that he had changed his doctrine regarding the self. 
' ' There is nothing, ' ' he says, 1 ' ' I would more willingly 
lay hold of, than an opportunity of confessing my 
errors. ' ' And what are his errors ? " I have not yet 
been so fortunate/' he replies, "as to discover any 
very considerable mistakes in the reasonings delivered 
in the preceding volumes, except on one article." 
That article is "the section concerning personal iden- 
tity." And with reference to it, he admits only 
"mistakes in the reasonings/' not an error in the 
doctrine. In fact, he still maintains the same doc- 
trine of the self as he held in the Treatise. For he 
asserts: 2 "When I turn my reflection on myself, I can 
never perceive this self without some one or more 
perceptions; nor can I ever perceive anything but 
the perceptions. It is the composition of these, there- 
fore, which forms the self." Consequently, it may 
reasonably be concluded that, since Hume's view of 
the self, when he wrote the appendix, was precisely 
the same as when he composed the Treatise, it had 
probably undergone no change when he prepared the 
Inquiry. That he should incidentally imply the ex- 
istence of a real self or personal identity, in the later 
work, and yet hold the idea of the same to be an 
illusion, is not any more remarkable than that he 
should occasionally imply the existence of a real 
power and necessary connection, and yet explain the 
ideas of these as actual fictions. Thus much with 
regard to the main argument. 

1 I, p. 5.-).-). 2 j y p 558. 



248 hume's treatise and inquiry. 

But there is yet some confirmatory evidence in 
favor of Brede and Grimm's position. In proposition 
(7) it is said that Hume often speaks of impressions 
and ideas being present to the mind, without once 
saying that the mind or self is a sum of perceptions. 
In the Inquiry, it is true, there ar.e occasional refer- 
ences to the self; but they are so indefinite, that a 
satisfactory conclusion cannot be drawn from them 
either way. 1 Some of these references favor one view, 
others the other. Thus Hume asserts : 2 "We attribute 
power to a vast number of objects, ... to the Su- 
preme Being, ... to the mind in its command over, 
its ideas and limbs, in common thinking and motion. ' ' 
Here it would seem that the mind is regarded as a 
real subject having command over its ideas and activi- 
ties. On the other hand, however, he states: 3 "The 
authority of the will over its own faculties and ideas 
is not a whit more comprehensible than the opera- 
tions of mind on body : So that, upon the whole, there 
appears not, throughout all nature, any one instance 
of connection, which is conceivable by us." He also 
declares 4 that "the mind has never, any thing present 
to it but the perceptions," and further, 5 that the rela- 
tions of resemblance, contiguity, and causation "are 
the only bonds, that unite our thoughts together, and 
beget that regular train of reflection or discourse, 
which, in a greater or less degr.ee, takes place among 
all mankind." This is the same doctrine as that of 
the Treatise. True, Hume does not attempt to ex- 
plain how these relations, which are "the only bonds" 
that unite perceptions, produce a self, or an idea of 

1 Of. pp. 9, 10, 54, 55, 56 n., 57, 60, 61, 76, 124. 

2 P. 56 n. s p. 61. * P. 125. 5 p, 4 3 ; c f m p< is. 



SPIRITUAL SUBSTANCE, PERSONAL IDENTITY. 249 

personal identity. Therein lay his difficulty, as he 
acknowledged, in the appendix. And he seems simply 
to have claimed "the privilege of a skeptic/ ' on con- 
fessing that the difficulty was "too hard" for his 
understanding. 1 

In this connection a casual reference in the posthu- 
mous work, the Dialogues concerning Natural Reli- 
gion, a reference which Hume's critics appear to have 
overlooked, is worthy of notice. In the discussion on 
the attributes of God Demea made the reply: 2 "In 
reality Cleanthes, consider what it is you assert, when 
you represent the Deity as similar to a human mind 
and understanding. "What is the soul of man? A 
composition of various faculties, passions, sentiments, 
ideas ; united, indeed, into one self or person, but still 
distinct from each other. . . . How is this com- 
patible with that perfect immutability and sim- 
plicity, which all true theists ascribe to the Deity V 7 
Of course, it may be objected that possibly Demea 
does not here speak for the author. But the weight 
of evidence is clearly on the other side, since Hume 
nowhere called in question the validity of Demea 's 
argument. It must be admitted, however, that the 
preceding reasoning is not quite convincing. From 
the incidental references in the Inquiry and Dialogues 
a probability at most, not a certain conclusion can 
be reached. And this probability inclines, perhaps, 
as much to the one side as to the other. For addi- 
tional evidence, therefore, we turn to the second part 
of Brede's argument in proposition (7), viz., Hume's 
claim that the Inquiry, rather than the Treatise, rep- 
resents his true position in his matur.er years. 

1 1, p. 559. 2 II, p. 400. 



250 hume's treatise and inquiry. 

The advertisement to the posthumous and authori- 
tative edition— 1777— of the Essays and Treatises on 
Several Subjects was for a long time an enigma to 
the students of Hume 's philosophy. It is only within 
recent years, through the liberality of the Earl of 
Rosebery, that the secret has been disclosed, by the 
publication of Letters of David Hume to William 
Strahan, edited by G. B. Hill. The advertisement in 
the Essays and Treatises begins as follows: "Most of 
the principles, and reasonings, contained in this vol- 
ume, were published in a work in three volumes, 
called A Treatise of Human Nature: a work which the 
author had projected before he left college, and which 
he wrote and published not long after." And it 
concludes: "Henceforth, the author desires, that the 
following pieces may alone be regarded as containing 
his philosophical sentiments and principles." Many 
writers, naturally, have taken this declaration to 
mean a repudiation of the Treatise, and an avowal 
that the Inquiry alone is the true exponent of Hume's 
philosophical doctrines. Such a supposition, how- 
ever, is entirely erroneous. In 1740, Hume wrote to 
Hutcheson, respecting the Treatise, as follows: 1 "I 
wait with some impatience for a second edition, prin- 
cipally on account of some alterations I intend to make 
in my performance." Hume had not repudiated the 
Treatise then. True, he intended to make some alter- 
ations in it. But these were only on account of 
"negligences" in "the reasoning," or in "the ex- 
pression," not on account of a change in opinions or 
principles. 2 In 1742, in a letter to Home, he said : 3 

i Burton, Life, I, p. 117. 2 Ibid., I, p. 337. 
» Ibid., I, p. 143. 



SPIRITUAL SUBSTANCE, PERSONAL IDENTITY. 251 

"The Essays [Moral and Political] are all sold in 
London, . . . There is a demand for them; . . . 
They may prove like dung with marl, and bring for- 
ward the rest of my philosophy, which is of a more 
durable, though of a harder and more stubborn na- 
ture." Hume at this time judged rightly that the 
Treatise was "more durable" and harder than the 
Essays. He had not then repudiated it. In 1751, 
he wrote Elliot i 1 " I believe the Philosophical Essays 
[the Inquiry] contain every thing of consequence re- 
lating to the understanding, which you would meet 
with in the Treatise ; and I give you my advice against 
reading the latter. By shortening and simplifying 
the questions, I really render them much more com- 
plete. Addo dum minuo. The philosophical prin- 
ciples are the same in both; but I was carried away 
by the heat of youth and invention to publish too 
precipitately. ... I have repented my haste a 
hundred and a hundred times." And in a letter, 
supposed by Burton to have been written late in life, 
but when, and to whom is not known, he states: 2 
' ' That you may see I would no way scruple of owning 
my mistakes in argument, I shall acknowledge (what 
is infinitely more material) a very great mistake in 
conduct, viz., my publishing at all the 'Treatise of 
Human Nature/ a book which pretended to innovate 
in all the sublimest paths of philosophy, and which 
I composed before I was five-and- twenty ; above all, 
the positive air which prevails in that book, and 
which may be imputed to the ardor of youth, so much 
displeases me, that I have not patience to review it. 
But what success the same doctrines, better illus- 

1 Ibid., 1, p. 337. 2 Ibid., I, p. 98. 



252 hume's treatise and inquiry. 

trated and expressed, may meet with, adhuc sub judice 
lis est/' Hume has now given up the Treatise, ap- 
parently because of "the positive air" which pervades 
it ; but he still maintains its principles and doctrines. 
Soon, however, some important events occurred. 
In 1764 Reid's Inquiry appeared, and in 1770 Beat- 
tie's Essay on Truth. In both these books, Hume's 
system of philosophy is severely criticised, particu- 
larly the principles expounded in the Treatise, since 
they are the ones more easily assailable. Hume in- 
dignantly resented the criticism of Beattie. Formerly 
he was displeased with "the positive air" of the 
earlier work; now he appears to be dissatisfied with 
' ' the reasoning. ' ' Under these circumstances he pre- 
pared the now famous advertisement, and sent it to 
Strahan, in 1775, for insertion in the coming edition. 
Hence, he complains : ' ' Several writers, who have hon- 
ored the author's philosophy with answers, have taken 
care to direct all their batteries against the juvenile 
work, which the author never acknowledged, and have 
affected to triumph in any advantages, which, they 
imagined, they had obtained over it: a practice very 
contrary to all rules of candor and fair-dealing, and 
a strong instance of those polemical artifices, which a 
bigoted zeal thinks itself authorized to employ. ' ' At 
the same time, in his letter to Strahan, Hume ex- 
pressed the wish that he had prefixed the advertise- 
ment to the previous edition— 1768,— and remarked: 1 
"It is a complete answer to Dr. Eeid and to that 
bigoted silly fellow, Beattie." It is evident, there- 
fore, that when Hume desired the Inquiry to be re- 
garded by the public as alone containing "his philo- 

i Hill, Letters of D. JET., pp. 289, 290; cf. p. 303. 



SPIRITUAL SUBSTANCE, PERSONAL IDENTITY. 253 

sophical sentiments and principles," he made this 
statement, not because he had given up the philosoph- 
ical sentiments and principles of the Treatise, but 
because the position of the later work was less vul- 
nerable than that of the earlier. Even in the adver- 
tisement he does not retract any of the doctrines of 
the Treatise; he merely hopes that "some negligences 
in his former reasoning and more in the expression" 
are corrected. He would undoubtedly still have ad- 
mitted, as he formerly asserted, that "the philosoph- 
ical principles are the same in both. ' ' But he would 
not perhaps defend this position ; for he was not only 
at all times averse to controversy, but exceedingly so 
in his later years. Thus the probability that Hume's 
view of the self was the same when he wrote the In- 
quiry as when he wrote the Treatise, a probability 
which resulted from the examination of explicit 
statements in the appendix and incidental references 
in the Inquiry and Dialogues, is now heightened to 
practical certainty, by the frank admissions of the 
author himself. 

Finally, Brede rejoins, in proposition (8), that if 
Hume still held the same view of the self as formerly, 
it is inexplicable why he did not make use of this 
doctrine in his argument, in the eleventh section of 
the later work, against belief in the immortality of the 
soul. The answer to this part of B rede's reasoning 
is threefold:— (1) Such an argument Hume probably 
thought too subtle or abstruse to suit the character of 
the Inquiry. (2) The argument, in itself, is neither 
satisfactory nor decisive. As John Stuart Mill re- 
marked: 1 "It is precisely as easy to conceive, that a 

1 Examination of Bir William Hamilton's Philosophy, p. 211. 



254 hume's treatise and inquiry. 

succession of feelings, a thread of consciousness, may 
be prolonged to eternity, as that a spiritual substance 
for ever continues to exist: and any evidence which 
would prove the one would prove the other." This 
much is implied in the Treatise, in the section on 
"The Immateriality of the Soul." (3) As a matter 
of fact, Hume employed this argument in the dis- 
cussion on the attributes of God in his posthumous 
work, the Dialogues concerning Natural Religion. 
"What is the soul of man"? asked Demea, 1 "A com- 
position of various faculties, passions, sentiments, 
ideas ; united, indeed, into one self or person, but still 
distinct from each other. . . . How is this com- 
patible with that perfect immutability and simplicity, 
which all true theists ascribe to the Deity?" 

If additional proof were required in order to show 
that Hume's view of the self and personal identity 
was the same when he wrote the Inquiry as when he 
wrote the Treatise, attention might be called on the 
one hand, to the close correspondence which exists 
between the two works in so far as the subjects are 
treated in both, and on the other, to the fact that the 
omissions in the Inquiry are easily explained without 
attributing to Hume any important change of doc- 
trine. But further, proof is not necessary. The In- 
quiry consists essentially of certain portions of the 
Treatise abbreviated and popularized. And Hume 
did not intend that it should take the place of the 
Treatise, any more than did Kant intend that the 
Prolegomena should take the place of the Critique of 
Pure Reason. On the contrary, when he composed 
the later work he hoped that it would help to bring 

1 II, p. 406; cf. p. 238, above. 



SPIRITUAL SUBSTANCE, PERSONAL IDENTITY. 255 

forward the earlier, as containing his complete system 
of philosophy, into public notice. And this, in course 
of time, it did. 

There only remains now for examination Hume's 
admission when he wrote to Home: "I like exceed- 
ingly your method of explaining personal identity, 
as being more satisfactory than any thing that had 
ever occurred to me. ' ' This statement may have been 
perfectly true. But even so, that does not necessarily 
imply that Home's method of explaining personal 
identity was acceptable to the author of the Treatise 
of Human Nature. Hume confessed, in the appendix, 
that his own explanation of personal identity was 
"a labyrinth" of inaccuracies and inconsistencies. 
He thought Home's explanation better, but he did 
not say how much better. On the other hand, when 
it is observed that Home's argument, in the essay 
on "Personal Identity' ' is only such a one as Hume 
professed to have completely refuted in the Treatise, 
and such as is palpably inconsistent with the funda- 
mental principles of the Inquiry; when it is remem- 
bered that Home was Hume's kinsman and patron 
who had written him a letter of introduction to Dr. 
Butler, and who had exerted all his influence, al- 
though in vain, to secure for the philosopher a uni- 
versity position; when it is noted that Hume wrote 
his letter to his patron just before leaving England 
on a military expedition which was undertaken with 
a view to improving his financial position ; when it 
is learned that Hume, after his unfortunate experi- 
ence with the Earl of Annandale— in which affair 
his "only crime" had been "too little dissimulation, 
and too strong an indignation at meeting with treach- 



256 hume's treatise and inquiry. 

ery and perfidiousness" where not expected, 1 — had 
become sufficiently a man of the world to be able to 
appreciate the value and importance of having friends 
in high places to advance his interests ; when, finally, 
it is borne in mind that Hume was always, not only 
exceedingly courteous, but also extremely generous, 
and even magnanimous, toward his philosophical 
critics and literary contemporaries— toward all except 
"the bigots,"— it will be quite evident that his con- 
cession to Home, concerning the latter 's explanation 
of personal identity, is to be regarded after, the man- 
ner of a graceful compliment, rather than in the light 
of a candid acknowledgment. 

§ 45. Conclusion.— The more important conclu- 
sions of the chapter may now be brought together. 
To Hume's statement: "I never catch myself at any 
time without a perception, ' ' Calderwood retorted that 
it ought to be enough "if he could catch himself with 
one." But Hume also asserted that he never could 
observe "any thing but the perception." In the 
Treatise he affirmed: 2 "The true idea of the human 
mind, is to consider it as a system of different per- 
ceptions or different existences, which are linked to- 
gether by the relation of cause and effect, and mu- 
tually produce, destroy, influence, and modify each 
other." Of course, "produce, destroy, influence, and 
modify" are not to be understood according to the 
ordinary signification of the terms; they must be in- 
terpreted in the sense of Hume's meaning of power, 
or cause and effect. As the author stated elsewhere : 3 
"No internal impression has an apparent energy, more 

1 Murray, Letters of David Hume, p. 52. 

2 P. 541. 3 P. 456. 



SPIRITUAL SUBSTANCE, PERSONAL IDENTITY. 257 

than external objects have." It follows, therefore, 
that there is no idea of self after the manner ordin- 
arily explained. 1 This idea is a fiction, arising 
through the influence upon the imagination of a series 
of resembling perceptions. 2 Consequently, the actual 
identity of self is similar to that of houses, rivers, 
plants, or animals. 3 And the supposed idea of per- 
sonal identity is a fiction of the imagination, arising 
from the influence of the relations of resemblance and 
causation. 4 

In the appendix, 5 Hume admits that his explanation 
of personal identity is "very defective." He asserts, 
however, that it is not in his power to renounce either 
of the two principles: (1) "All our distinct percep- 
tions are distinct existences"; (2) "the mind never 
perceives any real connection among distinct exist- 
ences." He acknowledges that these two principles 
are contradictory, but pleads "the privilege of a 
skeptic," to evade further difficulty. 

Although there is no treatment of self or personal 
identity in the Inquiry, yet from statements in Hume 's 
letters, from incidental references in his later works, 
and from the fact that he still maintained the two 
foresaid contradictory principles, the conclusion is 
inevitable that his doctrine of the self was substan- 
tially the same when he wrote the Inquiry as when he 
wrote the Treatise. But since he was never able to 
reconcile the two contradictory principles, he would 
manifestly always be unable to give a satisfactory 
account of personal identity; consequently, this was 

I P. 533. 2 P. 535. * 3 P. 540. * P. 541. 

s I, pp. 568, 559. 

• Of. pp. 53, 145, L52, 153, 206, 210, above 
17 



258 hume's treatise and inquiry. 

one of the chief causes why he omitted entirely any 
further discussion of the subject. Other causes that 
might be assigned for this omission, no doubt, were 
the abstract nature of the subject, and the particular 
circumstances under which the later work was written. 
Nowhere, perhaps, is Hume's dependence on eigh- 
teenth century modes of thinking more clearly shown 
than in his conception and treatment of the self. 
Mathematical and physical ideas still held sway in the 
speculative thought of the age. Hume is the uni- 
versal analyzer, who tries to reduce everything to its 
constituent parts, hoping thereby to be able to explain 
the significance of the phenomenon under investiga- 
tion. But just as the biologist, when dissecting an 
organism, always loses the factor of life, so did Hume 
when analyzing perceptions, frequently lose the ele- 
ment of meaning. He seemed to possess it when 
starting out on his research. He has lost it when he 
reaches the end of his pursuit. And he then knows 
neither where to look for it, nor how to find it. Hence, 
he concludes, erroneously, that it was never present. 
It is extremely interesting to note that, in course of 
time, Hume came to recognize that his method was 
not perfectly satisfactory. Had he lived a century 
later, under the influence of the biological sciences, 
he would undoubtedly have arrived at a truer view 
of the self, as an organism which is something over 
and above the mere elements that enter into its con- 
stitution. 



CHAPTER XII. 

MIRACLES, A PARTICULAR PROVIDENCE, AND A 
FUTURE LIFE. 

§46. Miracles.— Hume's doctrines of miracles, a 
particular Providence, and a future life are practical 
consequences of his philosophy of human nature, 
rather than constituent parts of it. Yet the author 
originally intended to treat these subjects, in part at 
least, in the earlier work. For certain reasons, how- 
ever, chiefly politic, 1 he omitted a formal statement, 
and satisfied himself with incidental references. 

According to Hume's principles of unphilosophical 
probability, the degree of conviction or belief attend- 
ing a judgment or conclusion is much stronger when 
the decision is arrived at after examining a few propo- 
sitions, than when it is reached by means of a long 
chain of connected reasoning, even granting that each 
argument, or link in the chain, in either case, has an 
equal degree of probability. 2 Consequently, the evi- 
dence for any historical fact will produce the less con- 
viction, other things beine; equal, the farther back the 
fact is removed in time. In Craig's 8 argument against 
"the Christian Religion," based upon the nature of 
historical evidence, each link in the chain of testimony 
is supposed to amount only to a probability. And 
Eume admits that, if this assumption be granted, 

" Burton, Life, T, p. 63. 2 I, pp. 440, 441. 

3 Theologian Christiana' Principia Mathematica. 

259 



260 hume's treatise and inquiry. 

" there is no history or tradition, but what must in the 
end lose all its force and evidence." 1 He does not, 
however, concede the validity of Craig's argument, 
for two reasons: (1) Historical testimony in some 
cases amounts to a proof; (2) when the links in the 
evidence are all of a similar nature, the strength of 
the conviction does not diminish in proportion to the 
length of the chain. 

It was undoubtedly in connection with this subject, 
that Hume intended to set forth his own reasoning on 
miracles. Writing to Campbell, in 1762, he gives an 
interesting account of the origin of his argument. ' * I 
was walking in the cloisters of the Jesuits' College of 
La Fleche, ' ' he says, 2 ' ' and engaged in a conversation 
with a Jesuit of some parts and learning, who was 
relating to me, and urging some nonsensical miracle 
performed lately in their convent, when I was tempted 
to dispute against him; and as my head was full of 
the topics of my Treatise of Human Nature, which I 
was at that time composing, this argument immedi- 
ately occurred to me, and I thought it very much 
graveled my companion; but at last he observed to 
me, that it was impossible for that argument to have 
any solidity, because it operated equally against the 
Gospel as the Catholic miracles;— which observation 
I thought proper to admit as a sufficient answer. I 
believe you will allow, that the freedom at least of 
this reasoning makes it somewhat extraordinary to 
have been the produce of a convent of Jesuits, though 
perhaps you may think the sophistry of it savors 
plainly of the place of its birth. ' ' Prudential consid- 
erations induced the author to omit his "reasoning 

1 I, p. 442. 2 Burton, Life, I, p. 57. 



MIRACLES, PROVIDENCE, AND FUTURE LIFE. 261 

concerning miracles" in the Treatise, being afraid it 
would give "too much offence," as "the world" was 
then "disposed." 1 

In the Inquiry, after referring to Tillotson's argu- 
ment against "the real preseyice/' the author flatters 
himself that he has discovered "an argument" against 
miracles "of a like nature, w r hich, if just, will, with 
the wise and learned, be an everlasting check to all 
kinds of superstitious delusion, and consequently, will 
be useful as long as the world endur.es." 2 For so 
long, he presumes, "will the accounts of miracles and 
prodigies be found in all history, sacred and profane. ' ' 
It should be noted, at the outset, that Hume's argu- 
ment against miracles is, strictly speaking, not a criti- 
cism of their objective possibility, but an examination 
of their subjective credibility. It is a disquisition 
on the laws of evidence or principles of human testi- 
mony. In order, to discuss the subject intelligently, 
a definition is necessary; two are given. 3 Huxley 4 
finds fault with the form of these definitions, but he 
neglects to notice that, later in the discussion, the 
author added an explanation of them. This explana- 
tion, it is true, appeared at first as a foot-note, and 
not until the edition of 1770 was it incorporated with 
the text. Hume regards a miracle as "a violation of 
the laws of nature"; 5 that is, a violation of "the usual 
course of nature," as that is recognized by scientists. 
in this sense, the definition is not open to Huxley's 
criticism. 

An opinion prevails generally that Hume claims to 

i Burton, Life, I, p. 03. 2 P. SO. 

* P. 93, and n. i Hume, pp. 128-130. 

6 P. 93. « P. 105. 



262 hume's treatise and inquiry. 

demonstrate that no amount of evidence is sufficient 
to prove a miracle. Such opinion, of course, is a mis- 
conception, albeit a misconception which in large 
measure is excusable, on account of the author's mode 
of treatment. Hume acknowledges, not only "that 
there may possibly be miracles, " but that there may 
be miracles which i i admit of proof from human testi- 
mony. ' n What he denies is, that miracles which are 
made "the foundation of a [popular] system of re- 
ligion" are capable of proof. 2 His argument falls 
into two divisions. The first is, in substance, as fol- 
lows : 3 A miracle is a violation of the established laws 
of nature ; the laws of nature rest upon ' ' a firm and 
unalterable experience"; a uniform experience 
amounts to "a full proof"; consequently there is a 
full proof against "the existence of any miracle." 
It may be assumed, however, that in some instances 
human testimony in support of a miracle amounts 
to "an entire proof" also. "In that case," says 
Hume, 4 "there is proof against proof, of which the 
strongest must prevail, but still with a diminution 
of its force, in proportion to that of its antagonist. 
. . . The plain consequence is, ... ' That no testi- 
mony is sufficient to establish a miracle, unless the 
testimony be of such a kind, that its falsehood would 
be more miraculous, than the fact, which it endeavors 
to establish : And even in that case ther.e is a mutual 
destruction of arguments, and the superior only gives 
us an assurance suitable to that degree of force, which 
remains, after deducting the inferior.' " Thus far, 
Hume 's argument is essentially sound. True, it is not 

i Ibid., cf. II, p. 249. 2 p. 105. 

3 P. 93. * Pp. 93, 94. 



MIRACLES, PROVIDENCE, AND FUTURE LIFE. 263 

above criticism with reference to form, since it con- 
tains an ' ' ambiguous middle. ' ' For the ' ' full proof, ' ' 
on which the laws of nature rest, is not the same kind 
of "full proof" which is capable of being established 
upon human testimony; that is, "full proof/' as in- 
deed the author implies, does not always mean exactly 
the same thing. But this objection is evaded, con- 
sciously or unconsciously, in the statement of the con- 
clusion. Hence the reasoning, thus far, may be re- 
garded as perfectly valid. 

The above argument is only the first part of Hume 's 
reasoning. In the second part, he claims to show that 
he has been "a great deal too liberal' ' in his conces- 
sion with respect to the validity of human testimony, 
and that "there never was a miraculous event" estab- 
lished on such evidence as was equivalent to a full 
proof. 1 After an examination of the nature of evi- 
dence, he thinks, upon the whole, that "no testimony 
for any kind of miracle [which is to serve as a founda- 
tion for a popular system of religion] has ever. 
amounted to a probability, much less to a proof." 
And he concludes: 2 "We may establish it as a maxim, 
that no human testimony can have such force as to 
prove a miracle, and make it a just foundation for 
any [popular] system of religion." This part of the 
argument is open to criticism. When treating of 
miracles, two kinds should be distinguished, external, 
and internal. 3 The former are events in the physical 
world, and as such are open to the observation of the 
people present. The latter are experiences in the 
lii'e of the individual, and hence appear directly only 

to his own consciousness. Proof of the former de- 

1 P. 04. I I\ jor,. 3 Qf. W, pp, S'.i. 108. 



264 hume's treatise and inquiry. 

pends on external evidence, proof of the latter on 
internal. Hume's reasoning applies only to external 
miracles, and to external testimony. Whether or not 
snch testimony has proved the existence of miracles 
which might serve as "the foundation of a [popular] 
system of religion" will not be discussed here, since 
the question lies beyond the scope of this inquiry. It 
is sufficient to remark, that the second part of Hume 's 
argument is sophistical, and that his final conclusion 
is vitiated by the "ambiguous middle" already ad- 
verted to. The "full proof" arising from human 
testimony may, at times, be complete and certain; 
while the "full proof" on which the laws of nature 
rest is, at most, only a probability, the conclusion 
from an imperfect induction. Hume still admits, as 
every thinker must admit, the possibility of miracles. 1 
But his conclusion is wider than his premises when 
he asserts, that no human testimony can prove a 
miracle, "so as to be the foundation of a [popular] 
system of religion. ' ' Whether or not there have been 
such miracles in the past is wholly a question of evi- 
dence, a question on which there may be honest dif- 
ferences of opinion. And whether or not there will 
be such miracles in the future cannot be determined 
by any reasoning whatever. 

Near the close of the discussion, Hume made the 
following singular confession: 2 "I am the better 
pleased with the method of reasoning here delivered, 
as I think it may serve to confound those dangerous 
friends or disguised enemies of the Christian Religion, 
who have undertaken to defend it by the principles 
of human r.eason." The meaning of this avowal is 

i P. 105. 2 p. 107. 



MIRACLES, PROVIDENCE, AND FUTURE LIFE. 265 

still a matter of uncertainty. A writer in the Dublin 
University Magazine affirms: 1 "The only thing [in 
the Essay on Miracles] likely to offend [Dr. Butler] 
or any right judging person, is the paltry subterfuge 
with which the essay closes, in which [the author] 
affects to patronize Christianity. . . . The single 
excuse for this style was the state of the laws in most 
countries in Europe, and certainly in Scotland. " On 
the other hand, Grimm 2 thinks that Hume does not 
attack the Christian miracles. And Calderwood 3 is 
of the opinion that Hume, in his reference to the 
Christian miracles, is perfectly sincere. The last view 
is the one most nearly correct; yet it is correct only 
in part. The distinction drawn above between ex- 
ternal, and internal miracles is of service here. It is 
against the former class only that Hume's argument 
is directed ; to the latter, it has no application. Hume 
rejects external miracles; he believes in internal 
miracles. And many of his readers— some less, some 
more spiritually minded than he— have felt the force, 
and have been convinced of the essential truth of his 
conclusion: 4 "The Christian Religion not only was at 
first attended with miracles, but even at this day can- 
not be believed by any reasonable person without one. 
Mere reason is insufficient to convince us of its ver- 
acity: And whoever is moved by Faith to assent to it, 
is conscious of a continued miracle in his own person, 
which subverts all the principles of his understand- 
ing, and gives him a determination to believe what is 
most contrary to custom and experience." 

i Vol. XXVII, p. 3G2 n.; cf. Orr, David Hume, pp. 198, 216. 

2 Zur Gesoh, (L ErkenntniaproblemSf p. 513. 

3 Hume, Preface, and p. 91. 

« 1\ 108; cf. II, p. 249; IV, p. 135. 



266 hume's treatise and inquiry. 

§ 47. A Particular Providence.— It is often said 
that Hume's theory of causation overturns the foun- 
dation stone of philosophical theism. Undoubtedly, 
any validity that the cosmological argument might be 
supposed to have ought to disappear for the author 
of the Treatise of Human Nature, since he asserts that 
it is easy "to conceive any object to be non-existent 
this moment, and existent the next, without conjoin- 
ing to it the distinct idea of a cause or productive 
principle. ' n And yet, it is by no means certain that 
Hume rejected the common argument for the exist- 
ence of a first cause, for in the Dialogues he made 
Philo declare : 2 ' ' Nothing exists without a cause ; and 
the original cause of this universe (whatever it be) 
we call God ; and piously ascribe to him every species 
of perfection. Whoever scruples this fundamental 
truth, deserves every punishment, which can be in- 
flicted among philosophers, to wit, the greatest ridi- 
cule, contempt and disapprobation." But inasmuch 
as the cosmological argument, irrespective of any 
criticism of the idea of cause and effect, has ceased 
to satisfy the philosophical mind, Hume's theory of 
causation need not necessarily affect his position on 
the question regarding the existence of a particular 
Providence. The few casual remarks on this subject, 
in the Treatise and appendix, may be compared with 
the fuller statement of the Inquiry. 

In the earlier work Hume asserts: 3 "If every idea 
be derived from an impression, the idea of a deity 
proceeds from the same origin ; and if no impression, 
either of sensation or reflection, implies any force or 
efficacy, it is equally impossible to discover or even 

i I, p. 381. 2 II, p. 391. 3 P. 454. 



MIRACLES, PROVIDENCE, AND FUTURE LIFE. 2C7 

imagine any such active principle in the deity.' ' But 
although he affirms that it is impossible to discover 
or imagine any active principle in "the deity," he 
declares that it is "absurd and impious " to exclude 
this principle from "the supreme being." 1 These 
references obviously imply the existence of God. It 
would seen, however, as if the Divine Existence, not 
being the object of any impression, must remain es- 
sentially unknowable. 

In the appendix Hume is more explicit. He de- 
clares: 2 "The order of the universe proves an om- 
nipotent mind ; that is, a mind whose will is constantly 
attended with the obedience of every creature and 
being. Nothing more is requisite to give a founda- 
tion to all the articles of religion, nor is it necessary 
we should form a distinct idea of the force and energy 
of the supreme Being. ' ' The vague theism foreshad- 
owed in this passage harmonizes with that portrayed 
in a letter to Muir, a few years later, and very prob- 
ably is similar to his view at the time he wrote the 
Treatise. To Muir— about 1744— he wrote: 3 "It 
must be acknowledged, that nature has given us a 
strong passion of admiration for whatever is excel- 
lent, and of love and gratitude for whatever is ben- 
evolent and beneficial; and that the Deity possesses 
these attributes in the highest perfection: and yet I 
assert, lie is not the natural object of any passion or 
affection. He is no object either of the senses or 
imagination, and very little of the understanding, 
without which it is impossible to excite any affection." 

When one turns from this passage to the Inquiry, 
the story of the ass, as Huxley remarks/ 1 that took to 

1 P. 4.-,."). * I, p. 450 n. 

3 Burton, Life, I, p. 102. *Hume, p. 144. 



268 hume's treatise and inquiry. 

the water, when it was laden with salt, suggests itself. 
Hume 's theism ' ' dissolves away in the dialectic river, ' ' 
until little is left but "the verbal sack" in which it 
was contained. In section xi— entitled "A Particular 
Providence and a Future State," or as designated in 
the first edition, "The Practical Consequences of 
Natural Religion,"— Hume is represented by Epi- 
curus, who makes a harangue to the Athenian people 
on the subjects of God and immortality. The reason- 
ing concerning a particular Providence is a rejoinder 
to the argument in Butler's Analogy. The deists had 
claimed that certain doctrines of revealed r.eligion 
were inconsistent with the attributes of the Supreme 
Being. Butler showed that the natural religion of 
deism was open to a similar objection, and drew the 
conclusion that since this criticism was not valid 
against natural religion, neither was it effective 
against revealed religion ; that just as there are blem- 
ishes in nature so one might expect to find defects in 
a divine revelation. On the other hand, Hume as- 
serts that the objection holds in both cases. His 
argument is precisely analogous to that which he had 
formerly made to the Jesuit priest on the subject of 
miracles. 

The speaker admits the existence of God— a divine 
existence he had "never questioned" 1 — but asserts 
that the attributes of God can be inferred only from 
the course or order of nature. The ontological and 
cosmological arguments, naturally, have no place ; but 
the teleological argument appeals strongly to Hume's 
mind, 2 as it did later to Kant's and to John Stuart 
Mill's. "Allowing, therefore," says Epicurus, 3 "the 

ip. 112. 

2 Ibid.; cf. II, pp. 392, 443; IV, p. 309. * P. 113. 



MIRACLES, PROVIDENCE, AND FUTURE LIFE. 269 

gods to be the authors of the existence or or.der of the 
universe ; it follows, that they possess that precise de- 
gree of power, intelligence, and benevolence, which 
appears in their workmanship." But there appear to 
be defects in the workmanship, evils and disorders in 
the world. 1 This, to every apologist, is the appalling 
crux of the problem. Although Epicurus asserts the 
existence of God, he denies a particular Providence 
and "supreme governor of the world, who guides the 
course of events, and punishes the vicious with in- 
famy and disappointment, and rewards the virtuous 
with honor and success, in all their undertakings. " 2 
At the same time, he does not neglect to assert: "I 
deny not the course itself of events, which lies open 
to every one's inquiry and examination. I acknowl- 
edge, that, in the present order of things, virtue is 
attended with more peace of mind than vice, and 
meets with a more favorable reception from the world. 
I am sensible, that, according to the past experience 
of mankind, friendship is the chief joy of human life, 
and moderation the only source of tranquility and 
happiness." It is said, in reply, that from the ob- 
servation of "a half-finished building," one could 
infer from the effect, although incomplete, that it was 
"a work of design." 3 But Epicurus rejoins that the 
world is a unique effect, and consequently, that only 
so far as it shows wisdom and goodness, just so far 
can one ascribe wisdom and goodness to the cause. 
"A body of ten ounces" raised in a scale may serve 
as a proof that the counter balancing weight exceeds 
ten ounces, but not that it exceeds "a hundred. 7 ' 
Similarly, the print of a foot on the sand can only 

i P. 114. ' P. 115. »P. 117. 



270 hume's treatise and inquiry. 

prove, when considered by itself, "that there was 
some figure adapted to it, by which it was produced. ' ' 
True, the print of a human foot indicates that it was 
probably accompanied by another foot, which also 
left its impress, although effaced by time or accident. 
But in this process of reasoning one ascends from the 
effect to the cause, and then descends from the cause 
to the effect with the help of other experience. Such 
mode of procedure is not permissible when dealing 
with a unique effect like the universe. 1 It but aids 
the assent of reason with "the wings of imagination. ' ' 
Finally, the writer suggests the query, as an objection 
to the argument of Epicurus, whether it be possible 
for a cause to be known only by its own particular 
effect? whether a cause can be of so singular and 
particular a nature as to have no parallel and no 
similarity with any other cause or object? 2 To this 
inquiry Epicurus makes no rely. It is evident, there- 
fore, that the last objection is meant to be the au- 
thor 's ; and it is probable that, in accordance with his 
theory of causation, he would answer his final question 
in the negative. Hume seems to hold a form of theism 
resembling that adopted later by John Stuart Mill. 
He affirms the existence of God. He doubts only the 
nature or attributes of God. 3 He asserts that God is 
intelligent, but does not say that he is all-wise. It is 
on the moral side of the question, however, that Hume, 
like many others, finds the most perplexing difficulty. 4 
And here it seems as if reason is for ever fated to put 
her finger on her lips, and in awe and reverence 
whisper, " silence.' ' Other minds clearer and pro- 

iPp. 118, 119. 2 p. 121. 

s Cf. II, p. 391. * Cf. II, p. 443. 



MIRACLES, PROVIDENCE, AND FUTURE LIFE. 271 

founder even than Hume's, and other spirits loftier 
and nobler far than his have met with scarcely any 
better success than did he, in dealing with this mo- 
mentous problem. 

In the Natural History of Religion, and in the 
Di-alogues concerning Natural Religion, Hume treated 
at considerable length the more important religious 
questions. The Dialogues is one of the great master- 
pieces in religious criticism. The author, of whom 
it has been said with much show of plausibility that 
he had " neither any twist of vice nor any bias for 
doing good, "— was well qualified for such a work. 
No doubt he was fully conscious of his success, and 
for that reason took special care that it should not be 
suppressed after his death. Besides, a peculiar per- 
sonal feeling must have become bound up with a work 
which needed a quarter of a century for its composi- 
tion, and which was then retained for another quarter 
of a century, partly for further improvement, partly 
because the author desired "to live quietly, and keep 
remote from all clamor.." 1 But although the Dia- 
logues presents a vivid picture of Hume's theological 
difficulties and intellectual strivings, it gives little in- 
sight into the real nature of his religious convictions. 
There is no general agreement as to which speaker 
represents the writer; not even is there unanimity 
regarding the position of the several interlocutors, 2 
—much less regarding the position of the author. 8 

i Cf. Hill, Letters of D. //., p. 330. 

2 Of, Adamson, Ency. Brit., art. JIumr; Burton, Life, T, 
]). 320. 

• Of. Burton, Life, I, p. 320; Knight, Hume, pp. 209, 213; 
MfeCosh, Agnosticism of If. (Did Euwley, pp. 13, 51; Stephen, 
History of English Thought, I. j>. 3 12: Jodl, Leben u. Phil. 



272 hume's treatise and inquiry. 

Several writers think that Cleanthes represents 
Hume. 1 Many, however, assert that Philo does; 2 
some think Cleanthes and Philo f and others all three. 4 
The last view, notwithstanding Hume 's disclaimer, 5 is 
undoubtedly the more correct one. For while the 
author does not fully assent to all that is said by any 
of the speakers, each of them, in turn, voices his 
thought and sentiments. 

It is Hume's letters and conversation which convey 
the most valuable information regarding the develop- 
ment and character of his religious opinions. To 
Elliot, in 1751, he wrote: 6 "You would perceive by 
the sample I have given you, that I make Cleanthes 
the hero of the dialogue : whatever, you can think of, 
to strengthen that side of the argument, will be most 
acceptable to me. Any propensity you imagine I 
have to the other side, crept in upon me against my 
will; and it is not long ago that I burned an old 
manuscript book, written before I was twenty, which 
contained, page after page, the gradual progress of 
my thoughts on that head. It began with an anxious 
search after arguments, to confirm the common opin- 
ion ; doubts stole in, dissipated, . . . returned again ; 

D. H., pp. 191, 192, 194; Paulsen, Dialoge iiber natiirliche 
Religion und Selbstmord, p. 16; Windelband, Gesch. d. n. 
Phil., p. 333; Lechler, Gesch. d. englischen Deismus, p. 436. 

1 Burton, Life, I, p. 329; Ritchie, Life of Hume, p. 43; 
Stewart, Works, I, p. 434 n. 

2 Huxley, Hume, p. 151 ; Priestley, Letters to a Philosophical 
Unbeliever, p. 127; Orr, David Hume, p. 201. 

3 Windelband, History of Philosophy, p. 494. 

< Knight, Hume, p. 209 ; Porter, Science and Sentiment, 
p. 298. 
5 Ritchie, Life of H., p. 43. 
e Burton, Life, I, pp. 331, 333. 



miraci.es, providence, and future life. 273 

and it was a perpetual struggle of a restless imagina- 
tion against inclination, perhaps against reason. . . . 
I could wish Cleanthes' argument could be so analyzed, 
as to be rendered quite formal and regular.' ' To 
Balfour, in 1753, he wrote: 1 "I must only complain 
of you a little for ascribing to me the sentiments, 
which I have put in the mouth of the skeptic in the 
Dialogue. I have surely endeavored to refute the 
skeptic, with all the for.ce of which I am master, and 
my refutation must be allowed sincere, because drawn 
from the capital principles of my system/' To Stra- 
han, in 1776, he wrote: 2 "I there [in the Dialogues] 
introduce a skeptic, who is indeed refuted, and at last 
gives up the argument, nay confesses that he was only 
amusing himself by all his cavils; yet before he is 
silenced, he advances several topics, which will give 
umbrage, and will be deemed very bold and free, as 
well as much out of the common road." And to 
John Stewart he wrote : 3 "I am not such a skeptic as 
you may perhaps imagine." When dining one eve- 
ning with the French Encyclopaedists, he asserted 
that he had never seen an atheist. 4 To Mrs. Mallet 
he denied being a deist. 5 To Ferguson, on a beauti- 
ful star-lit night, he exclaimed: "Oh, Adam, can 
any one contemplate the wonders of that firmament, 
and not believe that there is a God!" And when 
weeping over his mother's death, he is said to have 
replied to Boyle: 7 "Though I threw out my specula- 

• Ritchie, Life of iff., p. 43. 

* Hill, Letters of D. If., p. 330. 
3 Burton, Life, II, p. 464. 
'Quarterly Review, Vol. CIL, p. 310. 

5 I Tardy, Memoirs of CharlemOtlt, I, p. 235. 

6 Burton, Life, II, p. 451. 

T Carlyle, Autobiography, p. 274. 
18 



274 hume's treatise and inquiry. 

tions to entertain and employ the learned and meta- 
physical world, yet in other, things I do not think so 
differently from the rest of mankind as yon may 
imagine/ ' 

From these citations, it is clear that Hume 's doubts 
on religions questions appeared at a very early age, 
that he strove earnestly to overcome them, and that 
he never succeeded. It is probable, therefore, that 
his position regarding the existence of a particular 
Providence was the same when he wrote the Treatise 
as when he wrote the Inquiry. And it is evident that 
the vacillation and indefiniteness in his writings on 
religious subjects are due neither to indecision, nor 
to caprice, but to many-sidedness. Although he made 
Cleanthes the hero of the Dialogues, he would have 
assumed the role of Philo himself, had Elliot been 
with him to take the part of Cleanthes. 1 He en- 
deavored to refute the skeptic; but at the same time 
he advanced several topics which he knew would give 
"umbrage." Although he declared that the skeptic 
was refuted and put to silence, yet so strongly did he 
present the case for Philo, that many of his readers 
have thought the skeptic had the better of the argu- 
ment. Thus Huxley asserts: 2 "If Hume really knew 
of any valid reply to Philo 's argument in the follow- 
ing passages of the Dialogues [II. pp. 407, 408], he 
has dealt unfairly by the reader in concealing it." 
While Hume could exclaim with the Psalmist: "The 
heavens declare the glory of. God ; and the firmament 

i Burton, Life, I, p. 332. 

2 Hume, p. 148; cf. Adamson, Ency. Brit., art. Hume; Orr, 
David Hume, p. 201 ; McCosh, History of Scottish Philosophy, 
p. 145; Stephen, History of English Thought, I, p. 342, Win- 
delband, History of Philosophy, p. 494. 



MIRACLES, PROVIDENCE, AND FUTURE LIFE. 275 

showeth his handiwork"; he could equally confess 
with the agnostic : ' ' The whole is a riddle, an enigma, 
an inexplicable mystery. ' n And it is not at all sur- 
prising if the avowed skeptic expressed himself with 
true reverence and sincerity in the conclusion of the 
Dialogues: 2 "The most natural sentiment, which a 
well-disposed mind will feel on this occasion, is a 
longing desire and expectation, that heaven would be 
pleased to dissipate, at least alleviate this profound 
ignorance, by affording some particular revelation to 
mankind, and making discoveries of the nature, attri- 
butes, and operations of the divine object of our faith. ' ' 
§48. A Future Life.— There remains now but one 
topic for discussion, the question of a future life. 
Near the close of the Treatise, there is a section on 
the "Immateriality of the Soul/' a doctrine which 
Hume declares to be a true atheism, almost the same 
as the "hideous hypothesis" which had made Spinoza 
1 l universally infamous. ' ' 3 Hume with his system of 
impressions and ideas, some of which are extended 
and some unextended, laid claim to refute both the 
materialistic and the idealistic theories of the soul. 
If the soul be extended, he asks, how can it have un- 

i IV, p. 363. 

2 II, p. 407; cf. Knight, Hume, p. 220; Burton, Life, I, pp. 
281, 282; Calderwood, Hume, p. 91; Quarterly Review, Vol. 
CIL, p. 311; Falckenberg, History of Modem Philosophy, p. 
230; Windelband, Gcsch. d. n. Phil., I, p. 331.— For the con- 
trary view, cf. Ptinjer, Hist, of the Christian Phil, of Religion, 
p. 377; Maurice, Moral and Metaphysical Phil., II, p. 57~>; 
Dublin University Magazine, Vol. XXVII, p. 3G2 n.; Lange, 
Hist, of Materialism, U, p. 102; Jodl, Lebcn u. Phil. D. IL, 
p. 80; Orr, David Hume, pp. 190, 198. 

3 P. 524. 



276 hume's treatise and inquiry. 

extended perceptions? and if it be unextended, how 
can it have extended perceptions? Consequently, 
"the question concerning the substance of the soul is 
absolutely unintelligible." 1 He professes, however, 
that his arguments are not "any ways dangerous to 
religion, " and offers the following "apology" to re- 
move the apprehensions of those who might think 
they were : 2 ' * There is no foundation for any conclu- 
sion a priori, either concerning the operations or dura- 
tion of any object, of which it is possible for, the 
human mind to form a conception. Any object may 
be imagined to become entirely inactive, or to be an- 
nihilated in a moment ; and it is an evident principle, 
that whatever we can imagine, is possible. Now this 
is no more true of matter, than of spirit; of an ex- 
tended and compounded substance, than of a simple 
and unextended. In both cases the metaphysical 
arguments for the immortality of the soul are equally 
inconclusive; and in both cases the moral arguments 
and those derived from the analogy of nature ar.e 
equally strong and convincing." 

The value of this apology, on account of the peculiar 
circumstances under which it was made, cannot be 
exactly determined. 3 Hume's critics generally assert 
that the philosophy of the Treatise of Human Nature 
strikes at the very root of the doctrine of immortality. 4 
According to that system, there is no valid idea of 

i P. 532. 2 iud. 

s Of. Burton, Life, I, pp. 279, 280. 

* Cf. I, p. 292; Knight, Hume, p. 219; McCosh, Agnosticism 
of H. and Huxley , p. 51; Lange, Hist, of Materialism, II, p. 
162; Piinjer, Hist, of the Christian Phil, of Bel., pp. 377, 378; 
Brede, Der Unterschied d. Lehren Humes, p. 48; Tennemann, 
Manual of the Hist, of Phil., p. 373. 



MIRACLES, PROVIDENCE, AND FUTURE LIFE. 277 

personal identity, and the self is nothing but a bundle 
or collection of perceptions, which succeed one an- 
other without any real connection. Thus, to cite one 
of Hume's memorable passages: 1 "When my percep- 
tions are removed for any time, as by sound sleep ; so 
long am I insensible of myself, and may truly be said 
not to exist. And were all my perceptions removed 
by death, and could I neither, think, nor feel, nor see, 
nor love, nor hate after the dissolution of my body, I 
should be entirely annihilated, nor do I conceive what 
is farther requisite to make me a perfect nonentity." 
Of course, Hume does not say that perceptions are 
removed by death. Any one who pleases may assume 
that they still continue after the dissolution of the 
body. He merely contends that if the soul ceases to 
perceive, it ceases to be. And he further contends 
that his metaphysical reasoning is not prejudicial to 
the interests of religion, for the moral arguments and 
those derived from the analogy of nature are strong 
and convincing in proof of the immortality either of 
a material, or of an immaterial soul. 

In the appendix there is only a passing reference 
to the subject of a future life, and it is of a similar 
import to the remarks in the Treatise. "The anni- 
hilation/' says Hume, 2 "which some people suppose 
to follow upon death, and which entirely destroys this 
self, is nothing but an extinction of all particular 
perceptions; love and hatred, pain and pleasure, 
thoughl and sensation. These therefore must be the 
same with self; since the one cannot survive the 
other." True, in another passage he declares: 3 "The 
order of the universe proves an omnipotent mind; 

1 I, p. 534. ■ J, p. 659. 3 I, p. 456 n. 



278 hume's treatise and inquiry. 

that is, a mind whose will is constantly attended with 
the obedience of every creature and being. Nothing 
more is requisite to give a foundation to all the articles 
of religion.' ' Here Hume admits that the doctrine 
of immortality has a valid foundation, if it be one of 
"the articles of religion." But it is obvious from 
some passages in other of his writings, that he does 
not so regard this doctrine. 1 The conclusion, there- 
fore, seems to be that while the author neither affirms 
nor denies a personal belief in immortality, he implies 
that a proof of it from moral arguments, and from 
those derived from the analogy of nature is possible. 
In the Inquiry, Hume was not restrained by a de- 
sire to obtain for, his philosophy, either the good 
opinion of Dr. Butler, or the applause of the learned 
world. Accordingly, he discussed the question of a 
future life with his usual freedom. In the opening 
remarks of his address, Epicurus, the author's pro- 
locutor, observes: 2 "We shall not here dispute con- 
cerning the origin and government of worlds. "We 
shall only inquire how far such questions concern 
the public interest. And if I can persuade you, that 
they are entirely indifferent to the peace of society 
and security of government, I hope that you will 
presently send us back to our schools, there to ex- 
amine, at leisure, the question, the most sublime, but, 
at the same time, the most speculative of all philos- 
ophy. ' ' Then, after dealing briefly with the problem 
of a particular Providence, the speaker asks: 3 "But 
what must a philosopher think of those vain reasoners, 
who, instead of regarding the present scene of things 
as the whole object of their contemplation, so far 
i Of. IV, p. ill. * p. in. 3 p. H6. 



MIRACLES, PROVIDENCE, AND FUTURE LIFE. 279 

reverse the whole course of nature, as to render this 
life merely a passage to something farther; a por.ch, 
which leads to a greater, and vastly different build- 
ing; a prologue, which serves only to introduce the 
piece, and give it more grace and propriety? From 
their own conceit and imagination surely. For if 
they derived it from the present phenomena, it would 
never point to any thing farther, but must be exactly 
adjusted to them. ' ' And since the arguments on this 
subject are to be drawn from experience, or from the 
phenomena of nature, 1 Hume denies the validity of 
any pretended proof for the existence of a future life. 

It may here, of course, be objected that undue 
weight is attached to the remarks of Epicurus. It 
may be said that Epicurus is a historical character, 
and that the opinions to which he gives utterance are 
his own, rather than Hume's. The position appears 
to be well taken. The opinions expressed are, no 
doubt, those of Epicurus. The question now to be 
considered is, are they also those of Hume? 

Naturally, one turns to the essay on "The Im- 
mortality of the Soul" for additional information 
regarding the author's belief. In this essay, printed 
in 1755 but withdrawn before publication, Hume dot's 
not rest satisfied with attempting to show that the 
existence of a future life is incapable of proof. He 
now carries the war into the enemy's country by ad- 
vancing several arguments against the doctrine of 
i in mortality. He not only recedes from his position 
affirmed in the Treatise, that the moral arguments 
and those derived from the analogy of nature are 
Strong and convincing, but he undertakes to show that 

i P. 117. 



280 hume's treatise and inquiry. 

the arguments drawn from metaphysics, from morals, 
and from physical science are all futile. Certain 
phases of the moral argument, in particular, he sub- 
jects to severe criticism. "By what rule are punish- 
ments and rewards distributed?" asks Hume, 1 "What 
is the Divine standard of merit and demerit?" And 
he replies: "Punishment, without any proper end or 
purpose, is inconsistent with our ideas of goodness 
and justice ; and no end can be served by it after the 
whole scene is closed. . . . 

"Were one to go round the world with an intention 
of giving a good supper to the righteous and a sound 
drubbing to the wicked, he would frequently be em- 
barrassed in his choice, and would find, that the merits 
and demerits of most men and women scarcely amount 
to the value of either. . . . 

"The chief source of moral ideas is the reflection 
on the interests of human society. Ought these in- 
terests, so short, so frivolous, to be guarded by punish- 
ments, eternal and infinite? The damnation of one 
man is an infinitely greater evil in the universe, than 
the subversion of a thousand millions of kingdoms." 

It may, perhaps, be replied that Hume's strictures, 
however effective they may be against certain im- 
plications of the doctrine of immortality, do not in- 
validate the counter argument of Butler. Bishop 
Butler pointed out that rewards and punishments 
take place in this world, conduct being always fol- 
lowed by its natural consequences. And since a sys- 
tem of rewards and punishments, in the present life, 
is compatible with the nature of the Infinite Will, it 
may equally be so in a future life. The pleasures 

i IV, pp. 402, 403. 



MIRACLES, PROVIDENCE, AND FUTURE LIFE. 281 

and pains experienced here may continue throughout 
eternity, increasing, diminishing, or changing as they 
do now. Such reasoning, however, affords but slight 
consolation. For Hume's pitiless rejoinder, would 
come, even in the words of the inspired writer : ' ' The 
righteous perisheth, and no man layeth it to heart,' ' 
or "Wherefore doth the way of the wicked prosper? 
"Wherefore are they happy that deal treacherously"? 

It should also be observed that Hume's argument 
against the existence of a future life does not conclu- 
sively determine the character of his own belief. For 
with his peculiar double-sidedness, he immediately 
gave back with one hand what he took away with the 
other. Although he maintained that the doctrine of 
a future life could not be proved by reason, he opened 
the discussion with the significant remark: 1 "In real- 
ity, it is the gospel, and the gospel alone, that has 
brought life and immortality to light"; and he con- 
cluded the essay with the equally impressive state- 
ment : ' ' Nothing could set in a fuller light the infinite 
obligations which mankind have to Divine revelation ; 
since we find, that no other medium could ascertain 
this great and important truth. ' ' 

Before proceeding farther with the discussion, it 
may be advantageous to take a brief review of Hume 's 
position in his different writings. In the Treatise, 2 he 
asserts that the moral arguments for immortality, and 
those derived from the analogy of nature are "strong 
and convincing." In the Inquiry, 3 he declares that 
the existence of a future life cannot be proved— 
indeed ho seems to come very near, denying such exist- 
enee altogether. 4 And in the essay on "The Immor- 

i IV, p. 309. 2 i\ 333. 3 p. 11G# 4 pp. no, Hi. 



282 hume's treatise and inquiry. 

tality of the Soul/' he not only contends that the 
existence of a future life cannot be proved by reason, 
but also advances many arguments against its actu- 
ality ; while at the same time, he acknowledges that it 
is a " great and important truth," discovered by the 
light of "Divine revelation." The vacillating and 
conciliatory attitude of the Treatise must be attrib- 
uted mainly to Hume's "cowardice"— to use his own 
term,— along with his desire to obtain for his system 
of philosophy the favorable opinion of Dr. Butler. 1 
And the unrestrained mode of expression in the In- 
quiry is largely explained by his eagerness to produce 
a murmur among "the zealots." 2 But whether the 
extreme position of the later work is due, in some 
measur.e, to a firmer conviction, as the author grew 
older, not only that the immortality of the soul is 
incapable of proof, but also that there is really no 
future life for the individual, is a question which 
cannot easily be determined. Nor does the suppressed 
essay, with its Janus-face, appear, at first sight, to 
furnish any satisfactory solution of the difficulty. 

Following the method taught by Hume, in his 
reasoning on cause and effect, we find a clue, in sub- 
stituting for our assigned question, whether, the opin- 
ions of Epicurus were also those of the author? a 
related question, viz., was the author sincere when he 
declared, in the essay, that the doctrine of immortality 
is a great and important truth, made known by Divine 
revelation ? If Hume was not sincere in this expres- 
sion, he was probably not sincere in his remarks in 
the Treatise, and his real view is most nearly expressed 
in the Inquiry; that is, Epicurus speaks for the au- 

1 Burton, Life, I, p. 64. 2 My Own Life. 



MIRACLES, PROVIDENCE, AND FUTURE LIFE. 283 

thor, as well as for himself. But on the other hand, 
if Hume was sincere in the essay, it may fairly be 
inferred that he was sincere in the Treatise also, and 
that the account in the Inquiry differs from those in 
the Treatise and essay, not in being inconsistent— as 
some critics maintain— but in being indefinite and 
ambiguous. In that case, Epicurus must be regarded 
as speaking only for himself, not for the author. In 
support of each of these alternatives a few arguments 
may be adduced. With an examination of the evi- 
dence on both sides of the question, our assigned task 
will be concluded. 

I. In favor of the former supposition, viz., that 
Hume was not quite sincere in his reference to the 
doctrine of immortality as a " great and important 
truth" of revelation, may be stated three considera- 
tions : 

1. Hume openly professed that he did not believe 
in the doctrine of a future life. To Hardy he said i 1 
"Why troth, man, it is so pretty and so comfortable 
a theory, that I wish I could be convinced of its truth, 
but I canna help doubting. " Now if a person pub- 
licly rejects one of the fundamental tenets of a pop- 
ular or dominant religion, it will generally be found 
that his skepticism extends even farther than his pro- 
fession. For considerations of self-interest and feel- 
ings of sympathy naturally attach him to the same 
religious views as those of his friends and neighbors. 
There are exceptions, of course, to the general rule. 
And Hume, it must be admitted, may have come under 
the exception. Many circumstances lend support to 
such an opinion. He had no close family ties; he 

i Life of the Earl of Charhmont, I, p. 233. 



284: hume's treatise and inquiry. 

had no high or generous enthusiasms; he cherished a 
strong feeling of independence, possessed an indom- 
itable spirit of self-reliance, and took pride in being 
thought a skeptic. Hence the argument based on his 
outward profession is not conclusive. 

2. From the accounts of Hume 's death it seems that, 
in his last days, he had no expectation that after his 
decease he would live again. McCosh 1 narrates a story 
—though he questions the truth of it— told by a person 
who professed to have attended the philosopher on his 
death-bed, and according to which, the patient experi- 
enced, at times, the most " unutterable gloom." But 
the statement is unworthy of the slightest credence. 
Hume's correspondence with Strahan, during the lat- 
ter part of his illness is exceedingly interesting and 
significant. On June 12, 1776, writing with regard 
to the publication of the Dialogues, he said: 2 "It is 
an idle thing in us to be concerned about any thing 
that shall happen after our death ; yet this is natural 
to all men, and I often regretted that a piece, for 
which I had a particular partiality, should run any 
hazard by being suppressed after my decease." He 
still continued making corrections for the coming edi- 
tion of his works. On July 27, he sent three pages 
for his history, remarking: "You will wonder, that, 
in my present situation I employ myself with such 
trifles, and you may compare me to the modern Greeks, 
who, while Constantinople was besieged by the Turks 
and they themselves were threatened with total de- 
struction, occupied themselves entirely in disputes con- 
cerning the procession of the holy Ghost. Such is the 

1 History of Scottish Philosophy, p. 133. 

2 Hill, Letters of D. H., p. 337. 



MIKACLES, PROVIDENCE, AND FUTURE LIFE. 285 

effect of long habit. ' ' Strahan replied on August 1 1 1 
"This will be a very correct edition, and I will take 
care it shall be printed accurately and neatly; . . . 
By the by, does not this almost universal solicitude 
to live after we close our eyes to this present scene, 
mean something? I hope, I almost believe it does." 
On July 30, Hume sent a further correction. On Au- 
gust 12, he sent another, and bade farewell to his pub- 
lisher. "This, Dear Sir," he said, "is the last correc- 
tion I shall probably trouble you with : for Dr. Black 
has promised me, that all shall be over with me in a 
very little time : This promise he makes by his power 
of prediction, not that of prescription. And indeed 
I consider it as good news: For of late, within these 
few weeks, my infirmities have so multiplied, that 
life has become rather a burthen to me. Adieu, then, 
my good and old Friend. David Hume." Yet an- 
other correction, the last, was added in a post-script. 
Strahan replied on August 19, and asked the follow- 
ing peculiar question: 2 "Only permit me to ask you 
a question or two, to which I am prompted, you will 
believe me, not from a foolish or fruitless curiosity, 
but from an earnest desire to learn the sentiments of 
a man, who has spent a long life in philosophical in- 
quiries, and who, upon the extreme verge of it, seems, 
i in that awful and critical period, to possess all 
the powers of his mind in their full vigor, and in 
unabated tranquility. 

"I am more particularly led to give you this trouble, 
from a passage in one of your late letters, wherein 
you say. // is an idle thing in us to be concerned about 
any thing that shall happen a fin- oar death; yet (his, 

i Hill, Letters of D. II. , p. 340. 2 Burton, Life, II, p. 512. 



286 hume's treatise and inquiry. 

you added, is natural to all men. Now I would 
eagerly ask, if it is natural to all men, to be interested 
in futurity, does not this strongly indicate that our 
existence will be protracted after this life ? 

"Do you now believe, or suspect, that all the powers 
and faculties of your own mind, which you have cul- 
tivated with so much care and success, will cease and 
be extinguished with your vital breath? 

"Our soul, or immortal part of us, some say, is able, 
when on the brink of dissolution, to take a glimpse of 
futurity ; and for that reason I earnestly wish to have 
your last thoughts on this important subject." Hume 
received the letter a day or two before his death, but 
did not answer it. Soon after, his brother replied: 1 
"Though he possessed his faculties, and understand- 
ing and cool head, to the last, he was scarce in condi- 
tion to answer [your letter] , nor the question you put 
to him : but so far as I can judge, his sentiments with 
regard to futurity were the same, as when he was in 
perfect health and was never more at ease in his mind, 
at any period of his life." Thus with the public 
protestations of the philosopher while in health, fully 
accords his conduct on the approach of death. 

3. Furthermore, it may be added that Hume was 
not one of those who think that absolute sincerity on 
all occasions is expedient or desirable. In the begin- 
ning of his practical life— when residing with the 
Marquis of Annandale,— after experiencing some 
painful and disadvantageous consequences of his act- 
ing honestly and disinterestedly, he wrote: 2 "My only 
crime has been too little dissimulation, and too great 

i Hill, Letters of D. E., p. 359. 

2 Murray, Letters of D. E., and extracts, etc., pp. 52, 53. 



MIRACLES, PROVIDENCE, AND FUTURE LIFE. 287 

an indignation at meeting with treachery and per- 
fidiousness, where I did not expect it. . . . My con- 
nection with the family will be very short, and give 
me occasion all my life to reflect on the mischiefs 
arising from too great trust and confidence." After 
taking part in a military campaign, mingling in state 
diplomacy, and acquiring the art of making one 's way 
in the world, he wrote: 1 "It is putting too great a 
respect on the vulgar, and on their superstitions, to 
pique one's self on sincerity with regard to them," 
and added that, without a little "innocent dissimula- 
tion, or rather simulation," it is impossible "to pass 
through the world." This argument, it is true, will 
work either way. While it implies that Hume was 
not actuated always by motives of the strictest integ- 
rity or singleness of purpose, it does not indicate 
whether his evident insincerity, in the present in- 
stance, was manifested in his writings, or in his con- 
versation ; whether in his professed acceptance, in the 
essay, of the doctrine of immortality as a truth of 
revelation, or in his pretended rejection of it, in his 
daily life, as a speculative dogma without influence 
on conduct. Yet when this argument is taken in con- 
nection with the preceding ones, the inference seems 
inevitable, that Hume was not perfectly sincere in his 
reference to immortality as an important truth, dis- 
covered by the light of Divine revelation. 

II. Before giving final assent, however, to the con- 
clusion just arrived at, it may be deemed requisite to 
examine also the arguments in favor of the latter 
alternative, viz., that Hume was sincere in his refer- 
ence, in the essay, to the doctrine of immortality as a 

I Burton, Life, II, pp. 187, 188. 



288 hume's treatise and inquiry. 

divinely revealed truth. Two reflections suggest 
themselves : 

1. There is nothing inherently inconsistent in the 
belief that the existence of a future life cannot be 
proved by reason, but is a revelation from Heaven, 
a true and precious message from the heart of Nature 
to her children. On the contrary, many eminent 
thinkers before Hume 's time held this view, as indeed 
many have held it since. 

2. In support of the theoretical position just indi- 
cated, there are some practical considerations: Hume 
encouraged his servants to attend a place of worship ; 
he went to church regularly himself, and took part 
in the counsels of the established church of Scotland. 1 
The historian doubtless realized that the doctrine of 
immortality had exercised a marvellous influence on 
the progress and civilization of the western w T orld. 
The philosopher must at times have recognized that 
belief in a future state is the source of unspeakable 
comfort and ennobling encouragement to multitudes 
of sorrowing and weary travellers oppressed by life's 
troubled pilgrimage. And although the psychologist 
clearly perceived that this belief is not always pro- 
ductive of pleasure, nor of the most beneficial re- 
sults, yet he understood well that the threatened pun- 
ishments of the nether-world are, in general, not 
realized very keenly. In the Treatise, 2 the author 
naively observed that "in matters of religion men 
take a pleasure in being terrified," and that "no 
preachers are so popular, as those who excite the most 

1 McCosh, History of Scottish Philosophy, p. 155; Burton, 
Life, II, p. 453. 

2 P. 414. 



MIRACLES, PROVIDENCE, AND FUTURE LIFE. 289 

dismal and gloomy passions.' ' With such thoughts 
as the foregoing flashing, at least fitfully, across a 
receptive and many-sided consciousness, the subtle, 
sympathetic mind of Hume may have been moved 
with reverence to exclaim: 1 "Nothing could set in a 
fuller light the infinite obligations which mankind 
have to Divine revelation ; since we find, that no other 
medium could ascertain this great and important 
truth. 7 ' 

Notwithstanding the justness of the foregoing re- 
flections, there are serious objections to the validity 
of the conclusion— if that conclusion attribute to 
Hume anything more than a passing though pious 
sentiment, when he eloquently referred to the doctrine 
of immortality as a truth of Divine revelation. There 
is a passage in the Inquiry of more than usual signifi- 
cance, which calls first for consideration. Epicurus 
insists that he does not undermine "the foundations 
of society/' nor. loosen "the ties of morality, " when, 
in his "philosophical disquisitions/' he denies the 
existence of a future state. And the Athenian people 
reply: Even should it be conceded that the doctrine 
of immortality is wholly a speculative principle, and 
consequently should have no influence on practical 
life, yet in reality it has a very decided sway over the 
character and conduct of mankind. 2 Hume is here 
giving an account of the actual facts of human ex- 
perience, as he had observed them in everyday life. 
In the eighteenth century, philosophers and scientists 
had advocated perfect liberty of thought for the sake 
of individual well-being and the advancement of 
truth; while princes and priests had fostered a belief 

i IV, p. 40G. 2 IV, pp. 110, 111. 

19 



290 hume's treatise and inquiry. 

in the immortality of the soul for the welfare of the 
state and the prosperity of the chnr.ch. Hume, as a 
member of the former class, acknowledged that the 
common man, or the man of emotional temperament 
may be powerfully influenced in his conduct by the 
doctrine of future rewards and punishments, and that 
the highly speculative mind, or the man of abstract 
thought is but little affected in his daily work by the 
common beliefs of a hereafter. Moreover, Hume also 
knew that although the politicians, as well as the 
philosophers, had much reason on their side, yet 
neither party had all. For man, whether ignorant or 
learned, is a social being, and not a logical machine. 
As a social being, he is a creature of habit. And in 
many instances, when character is once formed, philo- 
sophical theories and religious beliefs— though they 
may have played a large part in molding the character 
—have exceedingly little influence on conduct. It is 
then of infinitely more moment what kind of person 
one is, than what sort of beliefs one has. For Hume, 
as for Epicurus or the philosophic sage, the doctrine 
of immortality was of extremely little consequence. 
The natural impulses of sympathy and benevolence, 
of self-love and self-respect were the great motive 
forces that dominated his life, that made him in the 
true sense of the word a good citizen, and in the 
ordinary acceptation of the term an honorable man. 
Furthermore, we incline to the view that, apart 
from revelation, the strongest ground for belief in a 
future life is the desire of the fond parent to meet 
again a departed child, or of the disconsolate spouse 
or lover, for a glad reunion in the spirit-land, where 
there will be no more separations and no more sorrow. 



MIRACLES, PROVIDENCE, AND FUTURE LIFE. 291 

Hume belonged to neither of these two classes of 
people. He once congratulated himself on the fact 
that, as a number of small fevers are said to prevent 
a great one, so in like manner, since he entertained 
a sentiment of regard for, all the members of the fair 
sex, he was not in danger of becoming enamoured of 
any one. With open heart and with characteristic 
freedom, the philosopher dissipated his affection on 
humanity; while with masterly hand and national 
genius, the man of affairs centred his care on self. 
Hume early knew that he had drawn a lucky lot from 
the lap of Lachesis, and the vast resources of his 
marvellous mind he diligently employed to make his 
path in life prosperous and pleasant. After a few 
slight mishaps in fitting out his craft, he sailed suc- 
cessfully on the bright waters of an ever-flowing tide, 
rarely rising high on mountain crests, nor ever sinking 
low in abysmal hollows. Favored with sunny sky 
and enlivening breeze he kept far from shoals, and 
free from breakers. 

Finally, when putting in to port, he remarked, in 
the Autobiography, "that a man of sixty-five, by 
dying," cut off only "a few years of infirmities. 9 ' 
He had had a good day, and was then "detached from 
life." Although he had seen his own good ship glide 
over the waves of time in a silvery track, he had 
observed many others, no less worthy than his, buf- 
feted by the storms of adversity, or broken on the 
rocks of misfortune, or perchance engulfed in the 
ocean of eternity, ere the hopes, the aspirations, and 
the enthusiasms of the mariner had been fairly 
kindled. And he may very reasonably have had no 
desire to venture on another voyage upon an unknown 



292 hume's treatise and inquiry. 

sea, when, judging of the future from the past, in 
accordance with the principles of his own philosophy, 
he had no rational ground to expect that the new 
scene of things would be much better than the old. 



CHAPTER XIII. 



CONCLUSION. 



§ 49. Summary.— The relations which obtain, either 
in the way of agreement or of difference, between the 
Treatise and Inquiry, may now be summarized. There 
is not any subject whatever on which there is perfect 
agreement. In the Inquiry, there are omissions, or 
additions, or there is a modification of doctrine, or. a 
difference in method, in the treatment of every topic. 
Leaving out of consideration those slight variations 
that are of no significance, it may be said that the 
position of both works is identical on the following 
points : intrinsic or primary aiim, cause of perceptions, 
association of ideas, abstract or general ideas, cause 
and effect, philosophical probability, liberty and neces- 
sity, and the reason of animals. The position of both 
works is practically the same on the following points : 
subject-matter, method, nature and classification of 
perceptions, mathematics, belief, material substance, 
and external existence. Agreement is implied, al- 
though not formally expressed, on the following 
points: the ideas of space and time, intuitive knowl- 
edge, the distinction between natural and philosoph- 
ical relations, between impressions of sensation and 
reflection, and betwen the ideas of memory and im- 
agination. On the subjects of unphilosophical prob- 
ability, self, and spiritual substance, it may be in- 
ferred, from the general tenor of the treatment of 
related questions, from incidental references in other 
writings, and from statements in Letters, that Hume's 

293 



294 hume's treatise and inquiry. 

view was the same when he wrote the Inquiry as when 
he composed the Treatise. From his remarks on per- 
sonal identity, in the appendix, it would seem that 
his view on that question underwent a change. The 
extent of this change, however, it is impossible to 
ascertain. 

The chief differences in the Inquiry are omissions 
and additions. The omissions are of two kinds: (1) 
Complete, for example, the treatment of philosophical 
relations, intuitive knowledge, unphilosophical prob- 
ability, and the ideas of spiritual substance, self, and 
personal identity. (2) Partial, for instance, the 
treatment of impressions of reflection, ideas of mem- 
ory, general or abstract ideas, ideas of space and time, 
mathematics, philosophical probability, general rules, 
material substance, and external existence. The addi- 
tions are: (1) Some practical application of Hume's 
theoretical principles, for example, the treatment of 
miracles, a particular Providence, and a future state ; 
(2) the transference of the discussion on liberty and 
necessity fr.om Book II of the Treatise of Hitman 
Nature to the Inquiry; (3) the fuller development of 
the argument on the idea of necessary connection; 
(4) a more accurate account of belief; and (5) a 
fuller or more explicit recognition of the function of 
instinct. Besides these differences, it may be noted 
that Hume's extrinsic or secondary aims are not the 
same as formerly, and that the division of "the ob- 
jects of human reason" into relations of ideas and 
matters of fact is substituted for the classification of 
complex ideas and the sub-division of philosophical 
relations. 

The reasons for the omissions are: (1) The author's 



CONCLUSION. 295 

desire to present the more important and interesting 
parts of his philosophy briefly, clearly, and in a pop- 
ular manner. (2) The inherent difficulties in some 
of the subjects themselves. (3) The discovery that 
the principle of connection among ideas, in the at- 
tempted explanation of the fiction of personal iden- 
tity, was "very defective." The reasons for the addi- 
tions are : ( 1 ) Hume 's desire to call attention to the 
significance of the philosophical principles of the 
Treatise; (2) his desire for fame and notoriety; (3) 
his comparative indifference to the reception which 
the Inquiry would receive from certain classes of 
people, the favorable opinion of whom he had wished 
to obtain for the Treatise; (4) his desire to answer 
objections that seem to have been provoked by the 
mode of treatment in the earlier wort; and (5) his 
clearer psychological insight regarding the nature of 
belief and the function of instinct, when he wrote the 
Inquiry. 

§ 50. Hume's System of Philosophy.— It may yet 
be asked, What is Hume's philosophical position? Is 
his system to be classified as idealism, realism, ma- 
terialism, positivism, or skepticism? Statements may 
be discovered in his writings in favor of every one of 
these philosophical theories. The most obvious ex- 
planation of this apparent inconsistency is the many- 
sidedness and liberal-mindedness of the man. Knight , 
when speaking of the difficulty of determining Hume's 
place in the Dialogues concerning Natural Religion, 
discerningly remarked: 1 "It must not be forgotten, 
. . . that he had a certain amount of sympathy with 
all the characters; and thai each of them (Demea 
1 Hume, p. 209. 



296 hume's treatise and inquiry. 

included) alternately mirrored his own ever-changing 
mood. This kaleidoscopic character of Hume's mind 
has not been sufficiently recognized. ' ' Only an inter- 
pretation like this can render intelligible the subtle 
turns of thought, the rapid changes in point of view, 
and the unexpectedly inconsistent expressions that 
are frequently met with in his philosopieal writings. 
The true position of our author will best be indicated 
by reference to the more important subjects which he 
treats, viz., epistemology, metaphysics, and philosophy 
of religion. 

I. Epistemology. On the question of epistemology, 
Hume may be said to be a positivist, at least after, 
his own fashion. His subject-matter is impressions 
and ideas; his method, observation and experiment. 
The chief problems of epistemology are: (1) The 
origin of knowledge; and (2) the nature or validity 
of knowledge. On the first question, Hume is a thor- 
oughgoing empiricist. In both the Treatise and In- 
quiry, he regards all knowledge as having its origin 
in impressions of sensation. On the second question, 
viz., the validity of knowledge, our, author is not so 
positive. There is no doubt, of course, that the doc- 
trine of both works is essentially idealistic and phe- 
nomenalistic. But in systems of phenomenalism, this 
part of the theory of knowledge is a variable factor. 
In order to represent accurately Hume's view on the 
question of the validity of knowledge, it is necessary 
to take account of his threefold treatment of certainty, 
or the three stages in his exposition, which we have 
called the epistemological, the logical, and the psycho- 
logical. 

1. The Epistemological Exposition. According to 






CONCLUSION. 297 

the account in the Treatise, all knowledge or reason- 
ing consists of relations,— relations among impressions 
and ideas. Of relations there are two classes, those 
that always remain the same so long as the impressions 
and ideas upon which they are based remain the same, 
and those that may change without any change in the 
impressions or ideas. The former class fall within 
the sphere of intuition and demonstration. They are 
objects of knowledge, as distinguished from probabil- 
ity. They are practically exact and certain, and con- 
stitute "the foundation of science. " Among the 
demonstrative relations, however, there is one sort— 
the science of geometry— which form an exception to 
the general rule, in that they are not exact, because 
they are based on the images of sense and imagination, 
that is, on a standard which is not precisely true. 
The other class of relations constitute what is called 
probable knowledge, or more strictly speaking, proofs 
and probabilities. All reasoning concerning proofs 
is based upon the relation of cause and effect, and 
consequently, cannot be more certain than the founda- 
tion on which it rests. Proofs and probabilities differ 
only in degree, the former being founded on the more 
permanent principles of the imagination, the latter on 
the less permanent. 

2. The Logical Exposition. In Part IV, Hume 
subjects "the faculty, which judges," as well as the 
content about which the judgment is made to a relent- 
less criticism. The result of this criticism is twofold : 
(1) Knowledge, properly so called, "degenerates into 
probability"; (2) all probabilities, that is, knowledge, 
proofs, and probability, art 1 resolved into "a total ex- 
tinction of belief and evidence/ ' But this extreme 



298 hume's treatise and inquiry. 

skepticism does not represent the true position of the 
author. It represents the position which would log- 
ically result, according to the principles of the philos- 
ophy of human nature, if belief were, as many sup- 
pose, an act of the understanding. 

3. The Psychological Exposition. Belief, Hume 
holds, is not an act of the understanding, but a feel- 
ing, an instinct, or a product of the imagination. 
Thus nature, by means of certain qualities of the 
imagination, prevents utter skepticism, and deter- 
mines one with a sort of necessity to view certain ob- 
jects in a particular manner, and to believe just as 
well as to breathe or feel. Hence, there exists a con- 
flict between the principles of the imagination, and 
the principles of the understanding or reason— al- 
though the latter are but ' ' the more established prop- 
erties" of the former. And not only does this con- 
flict exist between the imagination and reason, but 
each of these classes of principles, if followed exclu- 
sively, leads to contradiction or absurdity. Eeason, 
when it acts alone, entirely subverts itself; and the 
imagination alone runs into all sorts of absurdities 
and error. Thus there is "no choice left but betwixt 
a false reason and none at all." And Hume admits 
that he knows not what then "ought to be done." 
He only knows what generally is done, viz., that "this 
difficulty is seldom or never thought of." In other 
words, the result of logical reflection is utter skep- 
ticism. But nature demands action, and action is the 
radical cure for skepticism. Hume 's theory of knowl- 
edge, therefore, is theoretically and logically, complete 
skepticism; but practically and actually, it is a sys- 
tem of idealistic positivism. And the peculiar char- 



CONCLUSION. 299 

acteristic of this positivism is that while it cannot be 
rationally justified, yet it has sufficient authority and 
validity to serve all the purposes of life. 1 

In Books II and III of the Treatise of Human Na- 
ture;, the two classes of knowledge which are called 
relations of ideas and matters of fact were gradually 
substituted for the two classes of philosophical rela- 
tions, which were dealt with in Book I. Consequently, 
in the Inquiry all objects of human reason fall into 
these two classes, relations of ideas, and matters of 
fact. Kelations of ideas possess intuitive or demon- 
strative certainty, and thus constitute knowledge 
strictly so called. Reasoning concerning matters of 
fact is based upon the relation of cause and effect, as 
in the Treatise, and thus possesses only probable cer- 
tainty. But this probable certainty is again of two 
kinds, proofs, and probabilities in a narrower sense. 
All relations of ideas are sometimes spoken of as 
possessing exactness and certainty. Geometry, in- 
deed, as ordinarily treated, contains many contradic- 
tions and absurdities ; but Hume thinks that these may 
be removed by adopting his theory of general ideas. 
The manner in which this is to be done, however, he 
does not attempt to show ; nor is it to be neglected that 
he regards the fundamental ideas of geometry as being 
derived from the senses, and as being based on the 
general appearances of objects to the senses or. imag- 
ination. 

Relations of ideas and matters of fact are subjected, 
in section xii, to a criticism somewhat similar to that 
made in Part IV of the Treatise. Hume professes to 

1 Cf. Butler, Analogy, p. .'*. — " JUit to us, probability is the 

very guide of life." 



300 hume's treatise and inquiry. 

point out that there are contradictions and absurdities 
in the relations of ideas, as these subjects are com- 
monly dealt with by philosophers, and states that 
reason is so dazzled and confounded by these difficul- 
ties that "she scarcely can pronounce with certainty 
and assurance concerning any one object. ' ' And with 
regard to matters of fact, he maintains that there is a 
contradiction between the senses, instinct, or imagina- 
tion, on the one hand, and the reason or understand- 
ing, on the other. Hume thinks that most of the con- 
tradictions among relations of ideas may be removed 
by adopting his view of general ideas. And he affirms 
that the gr.eat subverter of Pyrrhonism or excessive 
skepticism is action, employment, "and the occupa- 
tions of common life. ' ' He asserts that his skeptical 
objections might be displayed at greater length, "if 
any durable good or benefit to society could ever be 
expected to result from them." For a similar reason 
he suppressed the essays on "Suicide" and the "Im- 
mortality of the Soul." 

It does not seem that there is any essential differ- 
ence of standpoint, or of doctrine in the Inquiry and 
Treatise, on the two general questions of epistemology. 
Differences of treatment, of course, are prominent; 
but most of these are easily explained. With regard 
to the topic of geometry, it is true, an apparent dif- 
ference of doctrine may be observed. And yet, even 
on this question, the position of the later work is 
practically the same as that of the earlier. The sub- 
ject is not dealt with in detail. This was done in the 
dissertation on "The Metaphysical Principles of 
Geometry," which Hume sent to Millar for publica- 
tion in 1755, but withdrew on account of some defect 



CONCLUSION. 301 

either "in the argument or in its perspicuity/' Con- 
sequently, the significance of the alterations in the 
form of statement, in the Inquiry, cannot be exactly 
determined. Also in the exposition of belief, although 
the doctrine remains in principle the same, there is a 
more explicit recognition of the emotional elements, 
and of the different types of belief, than in the earlier 
work. Finally, the faculty of imagination receives 
less consideration than formerly. In the Treatise, 
Hume maintained that the memory, senses, and under- 
standing are "all of them founded on the imagina- 
tion.' ' Yet he asserted that this principle is "incon- 
stant, ' ' and that men of bright fancies are like those 
angels, "whom the scripture represents as covering 
their eyes with their wings. ' ' Like the sage of Chel- 
sea, the philosopher of Ninewells clearly saw that by 
the imagination people everywhere are most easily 
1 ' governed and beguiled. ' ' In the Inquiry, the sphere 
of action for this faculty, on account of omissions, is 
considerably restricted, and a portion of its authority 
is shared in common with instinct. One might sup- 
pose, therefore, that this modification in treatment 
ensued naturally, as Hume grew older. The change 
is an interesting fact, but whether it has any signifi- 
cance, aside from that, seems to be beyond the power 
of determination. 

Our. author, like other great thinkers, lived before 
his time. lie was a man of the nineteenth century, 
rather than of the eighteenth. In the departments of 
political science, economics, philosophy, religion, and 
especially psychology, he was a pioneer. As a modern 
psychologist, he placed himself squarely on the broad 
ground of experience. As a keen observer, he recog- 



302 hume's treatise and inquiry. 

nized the facts. And as an impartial investigator, he 
accepted them all. The problem of knowledge, how- 
ever, was too difficult for, satisfactory treatment by 
means of the mechanism furnished him by the eigh- 
teenth century. In the course of the development of 
his doctrine, perplexities, absurdities, and contradic- 
tions arose. He pointed these out freely. And he 
acknowledged that he could not solve them. But he 
did not, on that account, proclaim that consciousness 
is fallacious, or that like Satan, it is " a liar from the 
beginning." Hamilton's celebrated dictum, "falsas 
in tino, falsus in omnibus/ 9 had rightly no place in 
his philosophy. He merely recognized that conscious- 
ness, indeed like most people in the world, does not 
tell the truth, on all occasions. His successors, how- 
ever, instead of giving their attention to the improve- 
ment of the science of man, with the help of better 
apparatus, seized the materials he left and used them 
as infernal machines, with which they sought to de- 
stroy the foundation he endeavored to construct. It is 
said that the politicians of some countries, when com- 
pelled by the pressure of public opinion to carry out 
any important reform, try all the possible wrong 
ways of doing the thing, before adopting the right one. 
In like manner, the philosophers seemed long intent 
upon trying all other possible theories, before going 
back to Hume. 

II. Metaphysics. Metaphysics has been employed 
in several different senses, for example, the science of 
being, the science of first principles, a systematic 
exposition of a priori judgments, etc., or as Hume 
sometimes used the term, any abstruse or profound 
reasonings. As now generally understood, metaphys- 



CONCLUSION. 303 

ics investigates two problems, one ontological, the 
other cosmological, viz., What is the ultimate nature 
of reality? and what is the form of reality, or the 
nature of the connection which exists between the 
totality of things? On both these questions Hume, 
in the Treatise, is not merely a skeptic, but also a dog- 
matist. The possibility of a metaphysics is excluded 
on his theory of knowledge. All knowledge arises 
from experience. Experience means ultimately sense 
experience, and one-sided at that. Consequently, the 
ideas of necessary connection, material substance, 
spiritual substance, self, and personal identity, in 
short, all primary metaphysical ideas are fictitious 
and invalid. And in every case, a professed explana- 
tion is given of how T the fiction arises, through the 
influence of imagination and custom. This latter ele- 
ment, the derivation of fictitious metaphysical ideas, 
is Hume's most important, as w T ell as his most dis- 
tinctive positive contribution to philosophy. 

In the Inquiry, Hume's position on the question of 
metaphysics is logically, although not actually the 
same as that in the Treatise. The subject-matter and 
method are similar. All knowledge arises from ex- 
perience. Experience is equivalent to sense experi- 
ence. And the author draws the conclusion, in a gen- 
eral way, that a metaphysics is impossible. He does 
not, however, treat the several problems of meta- 
physics after the same manner as in the earlier work. 
He takes up one question, that of causal connection, 
deals with it as he did in the Treatise, and arrives at 
the same conclusion with reference to it. The idea of 
necessary causal connection is a fiction, arising 
through the influence of imagination and custom. 



304 hume's treatise and inquiry. 

Now the question arises, What is Hume's position, 
in the Inquiry, on the other metaphysical questions, 
viz., material substance, spiritual substance, self, and 
personal identity? Three different answers are pos- 
sible. In the first place, it may be said that, in the 
appendix, he acknowledged that the principle of con- 
nection among ideas, when employed to explain per- 
sonal identity, was very defective, and that he knew 
neither how to correct that account nor, how to render 
it consistent. Hence, it may be thought that this con- 
fession is the key to the Inquiry, that it explains why 
a treatment of personal identity, self, and substance 
is omitted in the later work. The author's view, on 
these questions, underwent a fundamental change; 
and therefore, the position of the Inquiry is radically 
different from that of the Treatise. 1 Secondly, it may 
be said that since the fundamental principles are the 
same in both works, Hume thought it was not neces- 
sary to show a second time the application of these 
principles to all metaphysical questions in detail. He 
shows, in an exhaustive manner, the application of his 
principles to one of these questions, viz., necessary 
connection, with a result identical to that in the 
Treatise. He implies that they hold, in a similar way, 
when applied to the others. Consequently, the omis- 
sions in the later work are merely for the sake of 
brevity and popular treatment, and the position of 
both works is exactly the same. 2 Thirdly, there is an 
intermediate view, one that seems to be nearer the 

1 Cf. Grimm, Zur Gescli. d. Erkenntnisproblems, pp. 580, 
583; Brede, Der Unterschied d. Lehren H., pp. 47, 49. 

2 Cf. Green, " Introduction to Hume " ; Orr, David Hume, 
p. 45. 



CONCLUSION. 305 

truth than either of the preceding. The fundamental 
principles, as Hume himself said, are identical in both 
works ; therefore, the same conclusions as in the Trea- 
tise logically follow in the Inquiry. But the author, 
recognized a difficulty in the appendix, and this diffi- 
culty is a standing one. It applies, however, only to 
the ideas of spiritual substance, self, and personal 
identity. The principle of customary conjunction 
among ideas is as adequate to explain the fictitious 
idea of material substance, and the hypothesis of ex- 
ternal existence as to explain the fiction of necessary 
connection. Hence, on these questions, Hume's view 
was exactly the same when he wrote the Inquiry as 
when he wrote the Treatise. Over and above the 
many references, in the later work, in favor of this 
conclusion, convincing proof is easily accessible in his 
letters and essays. Writing to Home in 1746, he 
said: 1 "As to the idea of substance, I must own, 
that as it has no access to the mind by any of our 
senses or feelings, it has always appeared to me to be 
nothing but an imaginary centre of union amongst 
the different and variable qualities that are to be 
found in every piece of matter." Hume's principles 
of association, however, are not adequate to explain 
the fictitious ideas of self and personal Identity. 
Hence, on these subjects, the standpoint of the two 
works is obviously somewhat different. Here is a real 
cause for the omission, in the Inquiry, of a treatment 
of these problems. But it is not a sufficient reason for 
asserting that our author's view, on any of these ques- 
tions) is changed. It is highly probable, nay it is 
practically certain that his doctrines of spiritual sub- 

iT^jrtler, Memoir of Henry Home of Karnes, II, p. 124. 
20 



306 hume's treatise and inquiry. 

stance, self, and personal identity were the same when 
he wrote the Inquiry as when he wrote the Treatise. 
Consequently, while the position of both works, on the 
chief problems of metaphysics, is not formally iden- 
tical, yet essentially it is. The rejection of meta- 
physics, although not so thorough, is just as real in 
the Inquiry as in the Treatise. 

III. Philosophy of Religion. Although questions 
in philosophy of religion are treated in the Inquiry, 
in the Natural History of Religion, in the Dialogues, 
and in the essay on "The Immortality of the Soul," 
only three problems are discussed in the Inquiry, or 
referred to in the Treatise, viz., a particular Provi- 
dence, miracles, and a future life. A word on each. 

1. The Existence of God. Hume was never an 
atheist, and he objected to being called a deist. He 
undoubtedly regarded himself as a theist. His theism, 
however, was of a decidedly liberal character, a judi- 
cious blending of positive and negative elements. He 
believed in God as the author, or ground of the world, 
all-powerful, and possibly all-wise, but apparently 
indifferent to the individual wants of his creatures, 
and not the object of any affection. 

2. Miracles. Hume defined miracles as events con- 
trary to the established laws of nature, and implied a 
distinction between external miracles, and internal. 
External miracles he did not admit to have taken place 
in the past, but he conceded the possibility of their 
taking place in the future —although not as the basis 
of any popular system of religion. Internal miracles 
he asserted not only have occurred, but are occurring 
daily. His views on miracles and a particular Provi- 
dence, when he wrote both works, were the same. 



CONCLUSION. 307 

3. A Future Life. On the question of the immor- 
tality of the soul, Hume's position, in the Treatise, 
seems to be positive ; in the Inquiry, on the other, hand, 
it is negative. The change of statement, on this ques- 
tion, was due to the author's desire to obtain for the 
earlier work the favorable opinion of the learned 
world, or to his own conviction, as he grew older, that 
there was no valid ground— except possibly revelation 
—for belief in a future life, or. most probably, to both 
these causes. Had Hume lived in the nineteenth cen- 
tury instead of the eighteenth, he would have ac- 
counted himself, like Huxley and Spencer, an agnostic 
on matters of religion. 

IV. Conclusion. If Hume is to be placed in some 
category— and as Hunt, with much truth, observed, 
no mind more than his ct would have rebelled against 
being classed and labelled,"— it may be said that, with 
regard to epistemology, he is a positivist ; with regard 
to metaphysics, he is a skeptic; and with regard to 
religion, he is an agnostic. 

On these three subjects— epistemology, metaphysics, 
and philosophy of religion,— the position of the In- 
quiry is practically identical with that of the Treatise. 
True, if the later book be taken by itself, and read 
independently of the earlier, because of omissions, it 
appears to be much the more positive. The Inquiry 
alone, however, not only gives a very inadequate con- 
ception of the philosophy of human nature, but also 
an essentially false one. Thus Kant, who was ac- 
quainted only with the later work, 1 was entirely mis- 
taken regarding the author's position on certain im- 
portant epistemological questions. But the Inquiry 

1 Of, Adamson, The Philosophy of Kant, p. 202 n. 35. 



308 hume's treatise and inquiry. 

is the book which is by far the better known. More- 
over, it is the one which is generally regarded as con- 
taining the corrected, maturer, and truer statement 
of the principles of the science of man. It is un- 
doubtedly largely due to these circumstances that the 
treatment of Hume in nearly all the histories of phi- 
losophy is inadequate and defective. Hume's pe- 
culiar significance for the history of philosophy lies 
wholly and solely in the Treatise. In the preceding 
chapters of this monograph, we have endeavored to 
show that the Inquiry, when interpreted in the light 
of the Treatise, is essentially identical, both in point 
of view and in doctrine, with the earlier work. And 
that it should be so interpreted, we have also endea- 
vored to make manifest. The author more than once 
asserted that the philosophical principles, in both 
books, were the same. For some years after the pub- 
lication of the Treatise he looked forward to a second 
edition. In 1742, when his political essays were in 
great demand, he said that the Treatise of Human 
Nature was of "a more durable, though of a harder 
and more stubborn nature ' ' than the essays. He did 
not repudiate the Treatise until it had been attacked 
by Reid and Beattie. He was then an old man, too 
indolent, or too indifferent, or too busy with practical 
affairs to defend it. Hence, he acknowledged that it 
was defective; but yet the imperfections lay in the 
form, not in the doctrine. 

Hume's philosophical principles remained ever the 
same. But his system, begun with the most extrava- 
gant expectations, was concluded in the most extreme 
disappointment. The philosophy of human nature 
was declared to be "the only solid foundation" of the 



CONCLUSION. 309 

sciences, their ' ' capital or center. ' ' But the Treatise 
"fell dead-born from the press." The collapse, how- 
ever, was only temporary. The first offspring of 
Hume's mind lay for a time in a state of suspended 
animation. Then the weakling revived, grew, waxed 
strong, and soon became the enfant terrible of modern 
philosophy, a veritable hydra of Lerna, one of the 
immortal works in epistemology. Hume's system has 
often been demolished, nay broken in pieces as a pot- 
per's vessel; but phoenix-like it always rises from the 
ruins, and assails its old enemy, dogmatism and ra- 
tionalism, with renewed vigor. This indeed, thus far, 
may be said to be its chief function, if not its only 
raison d' etre. 

Contrasted with his proud claims for his philos- 
ophy, at the beginning of his task, the author's sober 
estimate of its worth, on the conclusion of his work, 
is significant and instructive. "I assure you," he 
wrote to Hutcheson, 1 "that without running any of 
the heights of skepticism, I am apt in a cool hour to 
suspect, in general, that most of my reasonings will 
be more useful by furnishing hints and exciting 
people's curiosity, than as containing any principles 
that will augment the stock of knowledge that must 
pass to future ages." 

Progress in philosophy, as in other lines of thought, 
is the resultant of two contrary, but complementary 
forces: invention, and criticism. These are the two 
great intellectual powers that bear onward the life- 
giving light of civilization. And like the wings of the 
eagle, each is no less necessary to upward movement 
than is the other. Hume's mind, however, was crit- 

i Burton, Life, T, p. IIS; cf. I, p. 552. 



310 hume's treatise and inquiry. 

ical, not constructive. He did not possess the inward 
eye of the poet, nor the spiritual vision of the prophet. 
He was constitutionally color-blind to some of the 
more important aspects of reality. But he had a 
supreme genius for destructiveness. His dialectic 
mind, like a logical machine, ground and analyzed 
with stoical indifference all things whatsoever, that 
fell within its relentless grasp. Letters and science, 
theology and medicine, law and politics;— all have 
had their great iconoclasts. But no department of 
knowledge has been more fortunate in this respect, 
than has been "divine philosophy/' because of the 
resistless logic, and all-devouring criticism of Hume. 



APPENDIX A. 

OUTLINE OF THE RELATION OF THE TREATISE TO 
THE INQUIRY. 

A Treatise of Human 



Nature. 

Introduction to the 
Treatise of Human 
Nature. 



Book I. 
Of the Understand- 
ing. 



An Inquiry concern- 
ing Human Un- 
derstanding. 

Of the Different Spe- 
cies of Philosophy; 
or Introduction to 
the theoretical part 
of the Treatise of 
Human Nature. 



Part I. 
Of Ideas, their Orig- 
in, Composition. 
Abstraction, Connec- 
tion, etc. 
§ 1. Of the Origin of our 

Ideas. 
[§ 2. Division of the Sub- 
ject.] 
[§ 3. Of the Ideas of the 
-Memory and Im- 
agination.] 
§ 4. Of the Connection 
or Association of 
Ideas. 



§ 2. 



Of the 
Ideas. 



Origin of 



Of the Association of 
Ideas. 



311 



312 



HUME S TREATISE AND INQUIRY. 



[§ 5. Of Kelations.] 
[§ 6. Of Modes and Sub- 
stances.] 
§ 7. Of Abstract Ideas. 



Part II. 

Of the Ideas of 
Space and Time. 
§1-5. Of the Ideas of 
Space and Time. 

§ 6. Of the Ideas of Ex- 
istence and Exter- 
nal Existence. 

Part III. 

Of Knowledge and 
Probability 
§ 1. Of Knowledge. 



§ 2. Of Probability; and 
of the Ideas of 
Cause and Effect. 

§ 3. Why a Cause is al- 
ways necessary. 

§ 4. Of the Component 
Parts of our Rea- 
sonings concerning 
Causes and Effects. 

§ 5. Of the Impressions 
of the Senses and 
Memory. 



§12. Of the Academical 
or Skeptical Phi- 
losophy. — Part II. 



§12. Of the Academical 
or Skeptical Phi- 
losophy. — Part II. 

§12. Of the Academical 
or Skeptical Phi- 
losophy. — Part I. 



§ 4- 



Skeptical Doubts con- 
cerning the Opera- 
tions of the Un- 
standing. — Part I. 



§ 4. 



Skeptical Doubts con- 
cerning the Opera- 
tions of the Un- 
standing. — Part II. 



RELATION OF TREATISE TO INQUIRY. 



313 



§ 6. Of the Inference from 
the Impression to 
the Idea. 

§ 7. Of the Nature of the 
Idea, or Belief. 

§ 8. Of the Causes of Be- 
lief. 
[§ 9. Of the Effects of 
other Relations, 
and other Habits.] 
[§10. Of the Influence of 

Belief.] 
§11. Of the Probability of 
Chances. 

12. Of the Probability of 
Causes. 

[§13. Of Unphilosophical 
Probability.] 

§14. Of the Idea of Neces- 
sary Connection. 
[§15. Rules by which to 
judge of Causes 
and Effects.] 

§16. Of the Reason of 
Animals. 



Part IV. 

Of the Skeptical and 
other Systems of 
Philosophy. 
§ 1. Of Skepticism with 
regard to Reason. 



§ 5. Skeptical Solution of 

these Doubts. — 

Part I. 
§ 5. Skeptical Solution of 

these Doubts. — 

Part II. 



0. Of Probability 
— Chances, and 
Causes. 



§ 7. Of the Idea of Neces- 
sary Connection. 
[§ 8. Of Liberty and 
Necessity.] 

§ 9. Of the Reason of 

Animals. 
[§10. Of Miracles.] 



§12. Of the Academical or 
Skeptical Philos- 
ophy. — Part II. 



314 



HUME S TREATISE AND INQUIRY. 



§ 2. Of Skepticism with 
regard to the 
Senses. 
[§ 3. Of the Ancient Phi- 
losophy.] 

§ 4. Of the Modern Phi- 
losophy.] 

§ 5. Of the Immateriality 
of the Soul. 

[§ 6. Of Personal Ident- 
ity.] 
§ 7. Conclusion of this 
Book. 



§12. 



Of the Academical or 
Skeptical Philos- 
ophy. — Part I. 



§11. 



Of a Particular 
Providence and of 
a Future State. 



§12. Of the Academical or 
Skeptical Philos- 
ophy.— Part III. 



APPENDIX B. 

BIBLIOGRAPHY. 

I. Editions and Translations of the Treatise and 
Inquiry. 

A Treatise of Human Nature: being an attempt to in- 
troduce the experimental method of reasoning into 
moral subjects. London: John Noone, 1739. 

Philosophical Essays concerning Human Understanding, 
— By the Author of the Essays Moral and Political. 
London: A. Millar, 1748, 1751. 

Essays and Treatises on Several Subjects. — By David 
Hume, Esq. ; in Four Volumes. London : A. Millar ; 
Edinburgh: A. Kincaid and A. Donaldson, 1753-54, 
1758, 1760, 1764. 

Ditto. Two Volumes. London. Printed for A. Millar, 
A. Kincaid, J. Bell, and A. Donaldson, in Edin- 
burgh. And sold by J. Cadell. 1768. 

Ditto. Four Volumes. London and Edinburgh: Cadell, 
Kincaid, and Donaldson, 1770. 

Ditto. Two Volumes. London and Edinburgh: Cadell, 
Donaldson, and Creech, 1777. 

Black and Tait. The Philosophical Works of David 
II nine. Edinburgh, 1826, 1836, 1854; London, 1856. 

Green and Grose. A Treatise of Human Nature, and 
Dialogues concerning Natural Religion. By David 
II nme. Edited, with preliminary dissertations and 
notes. Two Volumes. London: Longmans, Green, 
and Co., 1874, 1886, 1890. 

Green, T. IL, and Grose, T. II. Essays Moral, Politicals 
and Literary. By David Hume. Edited, with pre- 
liminary dissertations and notes. Two Volumes. 
London: Longmans, Green, and Co., 1874, 1889. 
315 



316 hume's treatise and inquiry. 

Jacob, L. H. David Hume uber die menschliche Na- 
tur, Zwei Bande. Halle : bei Hemmerde u. Schwet- 
schke, 1790-91. 

v. Kirchmann, J. H. Eine Untersuchung in Betrejf 
des menschlichen Yerstandes von David Hume, 
Heidelberg: Georg Weiss, 1888. 

Lipps, T. David Hume's TraTctat uber die menschliche 
Natur, I. Teil. " TJeber den Verstand," Uebersetzt 
von E. Kottgen. Hamburg u. Leipzig: Leopold 
Voss, 1895. 

Nathansohn, C. Eine Untersuchung uber den mensch- 
lichen Verstand, von D. Hume, Leipzig: P. Friesen- 
hahn, 1893. 

Eenouvier et Pillon. Traite de la nature humaine; et 
Essais philosophiques sur I'entendement. Traduc- 
tion de Merian corrigee. Paris: Au bureau de la 
critique philosophique, 1878. 

Selby-Bigge, L. A. Hume's Treatise of Human Nature, 
Oxford: Clarendon Press, 1888. 

Selby-Bigge, L. A. Hume's Enquiries concerning the 
Human Understanding, and concerning the Prin- 
ciples of Morals, Oxford: Clarendon Press, 1894. 

Sulzer. Untersuchung uber den menschlichen Verstand. 
Hamburg u. Leipzig, 1755. 

Tennemann, W. G. Untersuchung liber den menschlichen 
Verstand. Jena, 1793. 

II. Books. 1 

Adams, W. An Essay on Mr, Hume's Essay on Miracles, 

London, 1752, 1754. 
Adamson, K. On the Philosophy of Kant, Edinburgh : 

D. Douglas, 1879. 
Adickes, E. Kant-Studien, Kiel and Leipzig: Lipsius 

and Tischer, 1895. 

1 References to histories and encyclopaedias are omitted. 



BIBLIOGRAPHY. 317 

Aikins, H. A. The Philosophy of Hume. New York: 
Holt and Co., 1893. 

Albee, E. A History of English Utilitarianism. Lon- 
don: Swan, Sonnenschein, and Co.; New York: The 
Macmillan Co., 1902. 

Anon. An Analysis of the Moral and Religious Senti- 
ments contained in the writings of Sopho and David 
Hume, Esq., addressed to the consideration of the 
Kev. and Hon. members of the General Assembly of 
the Church of Scotland. Edinburgh, 1755. 

Axon. (Blair, or Home). Observations upon a Pamphlet 
entitled, "An Analysis of the Moral and Religious 
Sentiments contained in the writings of Sopho and 
David Hume, Esq." Edinburgh, 1755. 

Anon. Private Correspondence of David Hume with 
several Distinguished Persons between the years 
1761 and 1776. London: Colburn and Co., 1820. 

Bain, A. Mental and Moral Science. London: Long- 
mans, Green and Co., 1884. 

Balfour, J. A Delineation of the Nature and Obliga- 
tions of Morality; with reflections on Mr. Humes 
Inquiry concerning the Principles of Morals. 

Baumann, J. J. Die Lehren von Raum, Zeit and 
Mathematih in der neueren Philosophie. Berlin: 
Georg Reimer, 1868. 

Bkattie, J. An Essay on the Nature and Immortality 
of Truth. Edinburgh, 1770. 

BOSWELL, J. Life of Johnson. Edited by G. B. Hill. 
Oxford: Clarendon Press, 1887. 

JJim.de, W. Der Unterschied der Lehren Humes im 
Treatise and im Inquiry. Halle: Max Niemoyer, 
1896. 

BRENNER. Das Genie des Hume, order Sammlungcn der 
ziiglichsten Grundsatze dieses Philosopher*, Leip- 
zig, 1774. 



318 hume's treatise and inquiry. 

Brougham, H. Lives of Men of Letters of the time of 

George III. London and Glasgow: R. Griffin and 

Co., 1855. 
Brown, T. Lectures on the Philosophy of the Human 

Mind. Nineteenth Edition. Edinburgh: A. and 0. 

Black ; London : Longman and Co., 1851. 
Burton, J. H. The Life and Correspondence of David 

Hume. Edinburgh : W. Tait, 1846. 
Caird, E. The Critical Philosophy of Immanuel Kant. 

Glasgow : MacLehose and Sons, 1889 ; New York : The 

Macmillan Co. 
Caird, J. University Addresses. Glasgow: MacLehose 

and Sons, 1898. 
Calderwood, H. David Hume. New York: Charles 

Scribner's Sons, 1898. 
Campbell, G. A Dissertation on Miracles. With a 

correspondence by Hume, Campbell, and Blair. 

Edinburgh, 1797; Paisley, 1834. 
Carrau, L. La Philosophic Beligieuse en Angleterre. 

Paris : Felix Alcan, 1888. 
Case, T. Physical Realism. London: Longmans, Green 

and Co., 1888. 
Carlyle, A. Autobiography. Edited by J. H. Burton. 

Edinburgh, 1861. 
Compayre, G. La Philosophic de David Hume. Paris : 

E. Thorin, 1873. 
DeQuincey, T. "Miracles as Subjects of Testimony," 

Collected Writings, VIII. Edited by D. Masson. 

Edinburgh, 1889-90. 
Ferrier, J. F. Institutes of Mataphysic: The Theory 

of Knowing and Being. Edinburgh and London: 

W. Blackwood and Sons, 1875. 
Fischer, E. K. B. Francis Bacon of Verulam. Trans- 
lated by J. Oxenford. London: Longman, Brown, 

Green, Longmans, and Eoberts, 1857. 



BIBLIOGRAPHY. 319 

Fowler, T. Logic Deductive and Inductive. Oxford: 

Clarendon Press, 1895. 
Fraser, A. C. The Works of George Berkeley. Oxford: 

The Clarendon Press, 1871. 
Goebel, H. Das Philosophische in Humes Geschichte 

von England. Marburg, 1897. 
Gordy, J. P. Hume as Sceptic. Berlin: Berliner Buch- 

druckerei-Actien-Gesellschaft, 1885. 
Gore, W. C. The Imagination in Spinoza and Hume. 

Chicago: Chicago University Press, 1902. 
Green, T. H. Works of Thomas Hill Green. Edited 

by K. C. Nettleship. London : Longmans, Green and 

Co., 1885. 
Grimm, E. Zur Geschichte des Erkenntnisproblems von 

Bacon zu Hume. Leipzig: W. Eriedrich, 1890. 
Grimm et Diderot. Correspondance literairej philos- 

ophique et critique. Paris, 1829, 1882. 
Hamilton, E. J. The Perceptionalist, or Mental Science. 

New York : Hinds and Noble, 1899. 
Hamilton, W. Lectures on Metaphysics and Logic. 

Edited by Mansel and Veitch. Edinburgh and Lon- 
don: Blackwood and Sons, 1882. 

Discussions on Philosophy and Literature. New 

York: Harper and Brothers, 1868. 

Hardy, F. Memoirs of Charlemont. London: Cadell 

and Davies, 1812. 
Hill, G. B. Letters of David Hume to William Stralian. 

Oxford: The Clarendon Press, 1888. 
HoBHOUSB, L. T. The Theory of Knowledge. London: 

Methuen and Co., 1896. 
HODGSON, S. IL The Philosophy of Reflection. London: 

Longmans, Green and Co., 1878. 

The Metaphysics of Experience. New York: Long- 
mans, Green and Co., 1898. 



320 hume's treatise and inquiry. 

Holzke, T. D. Hume and T. B. Macaulay. Halle: 

Waisenhaus-Buchdruckerei, 1862. 
Home, H. Essays on the Principles of Morality and 

Natural Religion. Edinburgh: Kincaid and Don- 
aldson, 1751. 
Horne, G. " A Letter to Adam Smith on the Life, Death, 

and Philosophy of his Friend David Hume." 

Works, IV. 
Howison, G. H. Hume and Kant. Concord School of 

Philosophy, 1883. 
Hume, D. My Own Life. 1776. 
Huxley, T. H. Hume. London: Macmillan and Co., 

1881; New York: Harper and Brothers, 1879. 
Hyslop, J. H. Hume's Treatise of Morals. Boston: 

Ginn and Co., 1893. 
Jacob, L. H. Ueher Humes SJcepticismus. Ein Eriti- 

scher Versuch. Halle: Hemmerde and Schwetschke. 
Jacobi, F. H. David Hume uber den Glauben, oder 

Idealismus und Realismus. Breslau, 1787. 
Jahn, F. David Humes Eausalitdtstheorie. Leipzig, 

1895. 
James, W. The Principles of Psychology. New York: 

Holt and Co., 1890. 
Jodl, F. Leben und Philosophic David Humes. Halle: 

C. E. M. Pfeffer, 1872. 
Kant, I. Eritik der reinen Vernunft. 1781. 

Prolegomena. 1783. 

Klemme, M. Die Volkswirtschaftlichen Anschauungen 
David Humes. Halle, 1900. 

Knight, W. Hume. Edinburgh and London: Black- 
wood and Sons, 1886. 

Konig, E. Entiuickelung des Eausalproblems von 
Cartesius his Eant. Leipzig: O. Wigand, 1888. 

Ueber den Substanzbegriff bei Locke und Hume. 

Leipzig: W. Engelmann, 1881. 



BIBLIOGRAPHY. 321 

Kuhne, R. Ueber das Verhaltniss der Hume'schen und 

Kantischen Erkenntnisstheorie. Berlin: E. Krause. 
Ladd, G. T. A Theory of Reality. New York: Charles 

Scribner's Sons, 1899. 
Latimer, J. F. Immediate Perception as held by Reid 

and Hamilton considered as a Refutation of the 

Skepticism of Hume. Leipzig, 1880. 
Lechartier, G. David Hume, Moralist e et Sociologue. 

Paris: Felix Alcan, 1900. 
Long, W. J. Ueber Hume's Lehre von den Ideen und 

der Substanz in ihrem zusammenhang mit derjenigen 

Locke's und Berkeley's. Heidelberg, 1897. 
Lotze, H. Logic. Translation, edited by B. Bosanquet. 

Oxford : The Clarendon Press, 1888. 
Luers, A. David Humes Religionsphilosophische An- 

schauungen. Berlin: B. Gaertner, 1900. 
McCosh, J. Agnosticism of Hume and Huxley. New 

York: Charles Scribner's Sons, 1884. 
Mainzer, J. Die Jcritische Epoche in der Lehre von der 

Einbildungshraft aus Humes und Kants theoretischer 

Philosophic. Jena: E. Frommann, 1881. 
Masaryk, T. G. David Hume's Skepsis und die Wahr- 

scheinlichkeitsrechnung. Wien: C. Konegen, 1884. 
Masson, D. Recent British Philosophy. London and 

Cambridge: Macmillan and Co., 1865. 
Meinardus, II. David Hume als Religionsphilosoph. 

Coblentz : Kindt und Meinardus, 1897. 
Hhixong, A. Ilume-Studien: I. "Zur Geschichte und 

Kritik d. modernen Nominalismus." Wien, 1877. 

II. "Zur Pcelationstheorie." 1882. 
Meyer, E. Humes und Berheleys Philosophic der Mathe- 

matilc. Halle: Max Niemeyer, 1894. 
MlLL, J. Analysis of the Phenomena of the Human 

Mind. London: Longmans, Green, Reader, and Dyer, 

1878. 
21 



322 hume's treatise and inquiry. 

Mill, J. S. A System of Logic. New York: Harper 
and Bros., 1890. 

An Examination of Sir William Hamilton's Phi- 
losophy. London: Longman, Green, Longman, 
Roberts, and Green, 1865. 

Morehead. Dialogues on Natural and Revealed Religion. 
A continuation of Hume's Dialogues. Edinburgh, 
1830. 

Morris, G. S. British Thought and Thinkers. Chicago: 
S. C. Griggs and Co., 1880. 

Moyley, J. B. Eight Lectures on Miracles. London: 
Bivingtons, 1865. 

Murray, T. Letters of David Hume. Edinburgh: A. 
and C. Black, 1841. 

Newman, J. H. An Essay in Aid of a Grammar of As- 
sent. London: Longmans, Green, and Co., 1892. 

Nichols, H. The Psychology of Time. New York: 
Holt and Co., 1891. 

Orr. David Hume. 

Oswald, J. Appeal to Common Sense in Behalf of Re- 
ligion. Edinburgh, 1766-72. 

Paley, W. A View of the Evidences of Christianity. 
London: The Beligious Tract Society. 

Paoli, A. Hume e il Principis di Causa. Florence, 1880. 

Papillon, F. David Hume, precurseur d' Auguste Comte. 
Versailles, 1868. 

Patten, S. N. The Development of English Thought. 
London and New York: The Macmillan Co., 1899. 

Paulsen, E. Introduction to Philosophy. Translated 
by Thilly. New York: Holt and Co., 1898. 

Dialog e uber natilrliche Religion, uber SeTbstmord 

und Unsterblichheit der Seele von David Hume. 
Berlin: B. Salinger, 1894. 

Petzholtz, E. Die Hauptpunkte der Humeschen Er- 
henntnislehre. Berlin: G. Schade, 1895. 



BIBLIOGRAPHY. 323 

Pfleiderer, E. Empirismus und Skepsis in David 

Hume's Philosophie. Berlin, 1874. 
Porter, N. Science and Sentiment. New York : Charles 

Scribner's Sons, 1882. 
[Pratt, S. J.] An Apology for the Life and Writings 

of David Hume. With a Parallel between him and 

the late Lord Chesterfield: to which is added an Ad- 
dress to One of the People called Christians. By 

way of Beply to his letter to A. Smith. London, 

1777. 
Priestley, J. Letters to a Philosophical Unbeliever. 

London and Birmingham: J. Johnson, 1787. 
Badler, G. Ueber das Abstraktionsphaenomen in der 

Erkenntnistheorie David Hume's. Deggendorf, 1896. 
Baffel, J. Voraussetzungen, welche den Empirismus, 

Locke, Berkeley, und Hume zum Idealismus fuhren. 
Eeid, T. The Works of Thomas Reid. Edited by 

Hamilton, with notes and dissertations. Edinburgh : 

MacLachlan and Stewart, 1880 (eighth ed.). 
Bichter, P. David Hume's Kausalitdtstheorie und Hire 

Bedeutung f. d. Begrundung d. Theorie d. Induktion. 

Halle : M. Niemeyer, 1893. 
Bieiil, A. Der philosophische Kriticismus und seine 

Bedeutung fur die positive Wissenschaft. Leipzig: 

W. Engelmann, 187G. 
Bitciiie, T. E. An Account of the Life and Writings 

of David Hume, Esq. London: Cadell and Davies, 

1807. 
Bitter, C. Kant und Hume. Halle: Druck von G. 

Gutdeutsch in Luckenwalde, 1878. 
Bunze, P. W. K. M. Kants Kritik on Humes Skeptic- 

ismus. Berlin : Gebriider Grunert, 18S0. 
Sayous, E. Lcs Deistes Anglais el le Christianisme. 

Paris, 1882. 
Sciiultze, W. F. Hume und Kant iiber den Causal- 

begriff, 1870. 



324 hume's treatise and inquiry. 

Schulze, G. E. Die Hauptmomente der Skeptischen 
Denkart uber die menschliche Erkenntniss. Leipzig: 
Martini, 1805. 

Seth, A. Scottish Philosophy, Edinburgh and Lon- 
don: Blackwood and Sons, 1890, 1899. 

Simon, 0. Berkeley's Principles of Human Knowledge. 
London: W. Tegg and Co., 1878. 

Smellie, W. Literary and Characteristical Lives. Edin- 
burgh, 1800. 

Sneath, E. H. The Philosophy of Beid. New York: 
Holt and Co., 1892. 

Speckmann, A. JJeoer Hume's metaphysische Skepsis. 
Bonn : C. Georgi, 1877. 

Spencer, H. The Principles of Psychology. New York : 
Appleton and Co., 1890. 

Spicker, G. Kant, Hume und Berkeley. Berlin: C. 
Duneker, 1875. 

Stephen, J. Eitzjames. Horae Sahhaticae. London and 
New York: Macmillan and Co., 1892. 

Stewart, D. Dissertation: The Progress of Philosophy. 
Collected Works, Vol. I. Edinburgh: T. Constable 
and Co., 1854. 

Stuckenberg, J. H. W. Grundprohleme in Hume. 
Halle: E. C. M. Pfeffer, 1888. 

Tarantino, G. Saggio sul criticisms e sulV associa- 
zionismo di Davide Hume. Napoli, 1887. 

Thompson, J. P. Final Causes: A Critique of the Fail- 
ure of Paley and the Fallacy of Hume. London, 
1879. 

Thornton, W. T. Old-Fashioned Ethics and Common- 
Sense Metaphysics. London: Macmillan and Co., 
1873. 

Trench, B. C. Notes on the Miracles of our Lord. New 
York: Appleton and Co., 1895. 



BIBLIOGRAPHY. 325 

Tytler, A. F. Memoirs of the Life and Writings of 

the Hon. Henry Home of Karnes. Edinburgh: W. 

Creech. London: Cadell and Davies, 1807. 
Uhl, J. Die Grundzuge d. Psychologie David Humes. 

Prag: K K. Hofbuchdruckerei, A. Haase, 1887-88. 
Humes Stellung in d. englischen Philosophie. Prag: 

K K. Hofbuchdruckerei, A. Haase, 1890-91. 
Vaihixger, H. Commentar zu Rants Kritik d. r. Ver- 

nunft. Stuttgart: W. Spemann, 1881. 
Veitch, J. Hamilton. Edinburgh: Blackwood and Sons, 

1882. 
Villemaix, A. F. CEuvres, Vol. VI. Or Litterature au 

XV1I1 6 siecle. II. Paris: Didier, Libraire — Editeur, 

1851. 
Vixce, S. The Credibility of Christianity vindicated, 

in answer to Mr. Hume's Objections. Cambridge: 

Deighton and Nicholson, 1798. 
Volkelt, J. Erfahrung und Denken. Hamburg and 

Leipzig: L: Voss, 1886. 
Wallace, W. The Logic of Hegel. Oxford: The 

Clarendon Press, 1892. 
Watsox, J. An Outline of Philosophy. Glasgow: Mac- 

Lehose and Sons. New York: The Macmillan Co., 

1898. 

Kant and his English Critics. New York, 1881. 

Wlxdt, W. LogiJc. Stuttgart: F. Enke, 1880-83. 
Zlmels, J. David Humes Lehre vom Glauben und ihre 

Entwickelung vom Treatise zur Inquiry. Berlin: 

Mayer and Muller, 1903. 
Zimmerman, R. A. T. Ueber Hume's Stellung zu 

Berkeley und Kant. Wien, 1883. 

III. Periodicals. 
Academie royale des Sciences, 1792, p. 93. " Sur le 
Phenomenalisme de Hume," — J. B. Merian. 



326 hume's treatise and inquiry. 

American Catholic Quarterly Review, 10: 616. "The 

Skeptical Philosophy of Hume." — J. A. Cain. 
American Journal of Psychology, 4: 230. "Visualization 

as a chief source of the Psychology of Hobbes, Locke, 

Berkeley, and Hume." — A. Fraser. 
American Literary Magazine, 5 : 33. " Hume and the 

Puritans." — S. G. Buckingham. 
Analitic Magazine, 1 : 377. " The Character of Hume." 
Archiv fur Geschichte der Philosophic, 1 : 62, 216. " Kant 

und Hume um 1762." — B. Erdmann. 

2 : 330. " The Literature of Modern Philosophy in 

England and America." — J. G. Schurman. 

4: 177. "Bericht liber die neuere Philosophic bis 

auf Kant fiir die Jahre 1888 und 1889."— B. Erd- 
mann. 

Blackwood's Magazine, 3 : 653. " David Hume charged 
by Mr. Coleridge with plagiarism from St. Thomas 
Aquinas." 

46 : 91. " Hume's Argument against Miracles." — 

T. DeQuincy. 

105 : 665. " Historical Sketches in the Reign of 

George II. the Skeptic." — Mrs. Oliphant. (Living 
Age, 102: 29; Quarterly Review, 149: 287.) 

Bentley Magazine, 19 : 494. " The Philosophy of Hume." 

— W. C. Taylor. 
British and Foreign Evangelical Review, 36: 667. 

" David Hume." — E. Munro. 
Brownson Magazine, 12 : 445. " Humes Philosophical 

Works." 

23 : 482. " The Philosophy of Hume." 

Christian Examiner, 57 : 421. " Hume's Philosophical 

Writings." — J. Walker. 
Christian Observer, 7: 646. " Eitchie's Life of Hume." 
Christian Review, 20 : 219. " The Philosophy of Hume." 
Contemporary Review, 11 : 79. " David Hume." — J. Hunt. 



BIBLIOGRAPHY. 327 

Der Gedanke, 4: 3, 90, 160, 213; 5: 69, 159. "David 
Hume's Leben und Wirken." — E. Feuerlein. 

Dublin University Magazine, 27: 356, 576. "Hume's 
Life and Correspondence." — Anon. (Eclectic Maga- 
zine, 8: 80, 258). 

Eclectic Review, 7: 1. " Kitchie's Life of Hume." — J. 
Foster. 

84 : 317. " Hume and the Skeptical Philosophy." 

Edinburgh Annual Register, 1809, H. 549. " Original 

Letters of Shenstone, David Hume, and Joseph 

Spence." 
Edinburgh Monthly Review, 5: 127. "Private Corre- 
spondence of David Hume." 
Edinburgh Review, 85: 1. "Life and Correspondence of 

David Hume." — W. Empson. (Living Age. 12: 

499.) 
European Magazine, 1785, p. 250. 
Gentleman's Magazine, 1777, pp. 120, 158, 338; 1784, p. 

607. 
Journal of Speculative Philosophy, 10: 113. "Kant's 

Reply to Hume." — J. Watson. 

19 : 85. " Hume and Kant."— G. H. Howison. 

Kantstudien, 5: 177. "Hat Kant Hume's Treatise 

gelesen ? " — K. Groos. 

6 : 427. " Das Causalproblem bei Hume und Kant." 

— R. Reininger. 

7: 230. " Hat Kant Hume widerlegt? "—I. Mirkin. 

Leisure Hour, 14: 87. " The Tomb of Hume." 

Literary Gazette, 1822, p. 636. 

London Review, 5 : 200. 

Lutheran Quarterly, 21: 341. "Hume and his Philos- 
ophy."— J. A. Hall. 

Methodist Magazine, 28: 67. "Extract of a Letter of 
the late Dr. Home t<» A. Smith <>n fche Life, Death, 
and Philosophy of David Hume, Esq." 

Mind, 4: 270. "Huxley's J 1 111110."— Editor. 



328 hume's treatise and inquiry. 

9 : 531 ; 10 : 45. " Kant has not answered Hume." — 

J. H. Stirling. 

11 : 267. " Seth's Scottish Philosophy."— Editor. 



Monist, 6 : 516. " On the Origin and Import of the Idea 
of Causality."— F. Jodl. 

7 : 41. " From Berkeley to Hegel."— E. D. Fawcett. 

12 : 181. " Kant's Philosophy critically examined." 

— P. Cams. 

Philosophical Review, 2 : 167. " Epistemology in Locke 
and Kant."— A. Seth. 

4 : 241. " Agnosticism." — J. G. Schurman. 

5 : 113. " The Humist Doctrine of Causation." — 

W. W. Carlile. 

6 : 337. " The Ethical System of David Hume." 

— E. Albee. 

7 : 43. " The Empirical Theory of Causation."— 

J. B. Peterson. 

7: 561. "Scottish Moral Philosophy."— J. Seth. 

7 : 1, 135, 225. " The Genesis of the Critical Phi- 
losophy." — J. G. Schurman. 

8 : 1, 113. " Kant's Theory of the A Priori Forms 

of Sense." — J. G. Schurman. 

8 : 225, 337, 449. " Kant's A Priori Element of 

Understanding." — J. G. Schurman. 

8 : 604. " The Concepts of Substance."— H. Davies. 

10: 113, 229, 375, 488, 583. " The Doctrine of 

Space and Time." — G. Fullerton. 

12 : 272. " Altruism in Hume's Treatise."— E. B. 

McGilvary. 

Philosophische Monatschefte, N. F., 5: 324, 379. "Zur 
Kritik der modernen Causalanschauungen." — H. 
Griinbaum. 

Princeton Bevieiv, 1ST. S., 3 : 178. " Hume and Kant ; 
Philosophy of Causality." — J. H. Sterling. 

4 : 421. " Huxley's Exposition of the Philosophy of 

Hume."— K Porter. 



BIBLIOGRAPHY. 329 

Quarterly Review. 

73 : 536. " Hume and his Influence on History." 

— Lake. {Living Age, 1: 161.) 

78: 75. "Burton's Memoirs of Hume." — Lake. 

(Living Age, 10: 249.) 

149 : 287. " David Hume." 

Revue des Deux Mondes, XXYI e Annee. Seconde 
Periode, 6 : 107. (Nov., 1856.) " David Hume, sa 
vie et ses ecrits." — N. Cucheval-Clarigny. 

Revue Philosophique de Fi*ance, 8: 449. "Du pretendu 
Scepticisme de Hume." — G. Compayre. 

11 : 113 ; 12 : 18, 119. " La Philosophie en E cosse au 

XVIII e siecle et les origines de la philosophie 
anglaise contemporaine." — A. Espinas. 

Royal Irish Academy Transactions, 8 : 157. " Remarks 
on some skeptical positions in Hume's Inquiry con- 
cerning the Human Understanding." — R. Kirwan. 

Scots Magazine, 1756, pp. 248, 280. 

1757, p. 47. 

1802, pp. 794, 902. 

Sewanee Review, 10: 207. " Education of David Hume." 
— L. F. Snow. 

Southern Review, N. S., 11: 92, 309. "Hume's Philos- 
ophy." 

Tait's Edinburgh Magazine, N. S., 13 : 137, 205. " Bur- 
ton's Life of David Hume." — Anon. 

Vierteljahrsschrift filr Wissenschaftliclie Philosophie, 24: 
447; 25: 19, 145, 441. "Der Kausalbegriff in der 
neueren Philosophie und in den Naturwissenschaften 
von Hume bis R. Mayer." — J. W. A. Ilickson. 

Westminster Review, 46 : 144. " Life and Correspond- 
ence of David Hume." — R. N. 

14 1 : 1. " Professor Huxley on Hume and 

Berkeley." — G. G. Greenwood. 



330 hume's treatise and inquiry. 

Works of the Learned, 1739, November and December 

numbers. Review of Hume's Treatise of Human 

Nature. 
Zeitschrift fur Philosophie, 66: 102. " Pileiderer's Em- 

pirismus und Skepsis in D. H. Philosophie." — J. 

Wirth. 
76 : 248. " Meinong's Hunie-Studien," I.— E. 

Pfleiderer. 
109 : 213. " Kausalitat und Naturgesetzlichkeit." — 

F. Erhardt. 



WG 



1 ^ 






